diff --git a/Assets/Editor/ModifierAssetCreator.cs b/Assets/Editor/ModifierAssetCreator.cs
new file mode 100644
index 0000000..36e667f
--- /dev/null
+++ b/Assets/Editor/ModifierAssetCreator.cs
@@ -0,0 +1,123 @@
+#if UNITY_EDITOR
+using UnityEditor;
+using UnityEngine;
+
+public static class ModifierAssetCreator
+{
+    private const string BasePath = "Assets/ScriptableObjects/Modifiers";
+    private const string CatalogPath = "Assets/ScriptableObjects";
+
+    [MenuItem("YachtDice/Create Example Modifiers + Catalog")]
+    public static void CreateAll()
+    {
+        EnsureFolder(BasePath);
+        EnsureFolder(CatalogPath);
+
+        var m1 = CreateModifier("BonusPerOne", "Bonus Per One",
+            "+10 за каждый кубик со значением 1",
+            ModifierRarity.Common, 100, 50,
+            ModifierScope.SelectedCategory, ModifierEffectType.AddPerDieValue,
+            10f, 1, YachtCategory.Ones, false,
+            ModifierDurability.Permanent, 0);
+
+        var m2 = CreateModifier("MultiplierPerSix", "Multiplier Per Six",
+            "x6 за каждый кубик со значением 6",
+            ModifierRarity.Rare, 200, 100,
+            ModifierScope.SelectedCategory, ModifierEffectType.MultiplyPerDieValue,
+            6f, 6, YachtCategory.Ones, false,
+            ModifierDurability.Permanent, 0);
+
+        var m3 = CreateModifier("FullHouseFlat", "Full House Flat Bonus",
+            "+15 при закрытии Full House",
+            ModifierRarity.Uncommon, 150, 75,
+            ModifierScope.SelectedCategory, ModifierEffectType.AddFlatToFinalScore,
+            15f, 0, YachtCategory.FullHouse, true,
+            ModifierDurability.Permanent, 0);
+
+        var m4 = CreateModifier("YachtDoubler", "Yacht Doubler",
+            "x2 при закрытии Yacht (3 использования)",
+            ModifierRarity.Epic, 300, 150,
+            ModifierScope.SelectedCategory, ModifierEffectType.MultiplyFinalScore,
+            2f, 0, YachtCategory.Yacht, true,
+            ModifierDurability.LimitedUses, 3);
+
+        var m5 = CreateModifier("FiveBonusGlobal", "Five Bonus Global",
+            "+5 за каждую пятёрку при закрытии любой категории",
+            ModifierRarity.Uncommon, 250, 125,
+            ModifierScope.AnyCategoryClosed, ModifierEffectType.AddPerDieValue,
+            5f, 5, YachtCategory.Ones, false,
+            ModifierDurability.Permanent, 0);
+
+        var m6 = CreateModifier("CloseMultiplier", "Close Multiplier",
+            "x1.1 при закрытии любой категории (5 использований)",
+            ModifierRarity.Rare, 350, 175,
+            ModifierScope.AnyCategoryClosed, ModifierEffectType.MultiplyFinalScore,
+            1.1f, 0, YachtCategory.Ones, false,
+            ModifierDurability.LimitedUses, 5);
+
+        // Create ShopCatalog
+        var catalog = ScriptableObject.CreateInstance<ShopCatalog>();
+        var catalogSO = new SerializedObject(catalog);
+        var listProp = catalogSO.FindProperty("availableModifiers");
+        listProp.arraySize = 6;
+        listProp.GetArrayElementAtIndex(0).objectReferenceValue = m1;
+        listProp.GetArrayElementAtIndex(1).objectReferenceValue = m2;
+        listProp.GetArrayElementAtIndex(2).objectReferenceValue = m3;
+        listProp.GetArrayElementAtIndex(3).objectReferenceValue = m4;
+        listProp.GetArrayElementAtIndex(4).objectReferenceValue = m5;
+        listProp.GetArrayElementAtIndex(5).objectReferenceValue = m6;
+        catalogSO.ApplyModifiedProperties();
+        AssetDatabase.CreateAsset(catalog, $"{CatalogPath}/ShopCatalog.asset");
+
+        AssetDatabase.SaveAssets();
+        AssetDatabase.Refresh();
+        Debug.Log("Created 6 example modifiers and ShopCatalog.");
+    }
+
+    private static ModifierData CreateModifier(
+        string id, string displayName, string description,
+        ModifierRarity rarity, int shopPrice, int sellPrice,
+        ModifierScope scope, ModifierEffectType effectType,
+        float effectValue, int dieValue, YachtCategory targetCategory, bool hasCategoryFilter,
+        ModifierDurability durability, int maxUses)
+    {
+        var data = ScriptableObject.CreateInstance<ModifierData>();
+
+        var so = new SerializedObject(data);
+        so.FindProperty("id").stringValue = id;
+        so.FindProperty("displayName").stringValue = displayName;
+        so.FindProperty("description").stringValue = description;
+        so.FindProperty("rarity").enumValueIndex = (int)rarity;
+        so.FindProperty("shopPrice").intValue = shopPrice;
+        so.FindProperty("sellPrice").intValue = sellPrice;
+        so.FindProperty("scope").enumValueIndex = (int)scope;
+        so.FindProperty("effectType").enumValueIndex = (int)effectType;
+        so.FindProperty("effectValue").floatValue = effectValue;
+        so.FindProperty("durability").enumValueIndex = (int)durability;
+        so.FindProperty("maxUses").intValue = maxUses;
+
+        var targetProp = so.FindProperty("target");
+        targetProp.FindPropertyRelative("DieValue").intValue = dieValue;
+        targetProp.FindPropertyRelative("TargetCategory").enumValueIndex = (int)targetCategory;
+        targetProp.FindPropertyRelative("HasCategoryFilter").boolValue = hasCategoryFilter;
+
+        so.ApplyModifiedProperties();
+
+        AssetDatabase.CreateAsset(data, $"{BasePath}/{id}.asset");
+        return data;
+    }
+
+    private static void EnsureFolder(string path)
+    {
+        string[] parts = path.Split('/');
+        string current = parts[0];
+        for (int i = 1; i < parts.Length; i++)
+        {
+            string next = current + "/" + parts[i];
+            if (!AssetDatabase.IsValidFolder(next))
+                AssetDatabase.CreateFolder(current, parts[i]);
+            current = next;
+        }
+    }
+}
+#endif
diff --git a/Assets/Scripts/Economy/CurrencyBank.cs b/Assets/Scripts/Economy/CurrencyBank.cs
new file mode 100644
index 0000000..27cb60a
--- /dev/null
+++ b/Assets/Scripts/Economy/CurrencyBank.cs
@@ -0,0 +1,44 @@
+using System;
+using UnityEngine;
+
+public sealed class CurrencyBank : MonoBehaviour
+{
+    [SerializeField] private int startingBalance = 500;
+
+    private int balance;
+
+    public int Balance => balance;
+
+    public event Action<int> OnBalanceChanged;
+
+    private void Awake()
+    {
+        balance = startingBalance;
+    }
+
+    public void Add(int amount)
+    {
+        if (amount <= 0) return;
+
+        balance += amount;
+        OnBalanceChanged?.Invoke(balance);
+    }
+
+    public bool Spend(int amount)
+    {
+        if (amount <= 0) return false;
+        if (balance < amount) return false;
+
+        balance -= amount;
+        OnBalanceChanged?.Invoke(balance);
+        return true;
+    }
+
+    public bool CanAfford(int amount) => balance >= amount;
+
+    public void SetBalance(int value)
+    {
+        balance = Mathf.Max(0, value);
+        OnBalanceChanged?.Invoke(balance);
+    }
+}
diff --git a/Assets/Scripts/Inventory/InventoryController.cs b/Assets/Scripts/Inventory/InventoryController.cs
new file mode 100644
index 0000000..b87ecbb
--- /dev/null
+++ b/Assets/Scripts/Inventory/InventoryController.cs
@@ -0,0 +1,91 @@
+using UnityEngine;
+
+public sealed class InventoryController : MonoBehaviour
+{
+    [SerializeField] private InventoryView inventoryView;
+    [SerializeField] private ScoringSystem scoringSystem;
+    [SerializeField] private CurrencyBank currencyBank;
+
+    private InventoryModel model;
+
+    public InventoryModel Model => model;
+
+    public void Initialize(InventoryModel inventoryModel)
+    {
+        model = inventoryModel;
+
+        inventoryView.OnActivateClicked += HandleActivate;
+        inventoryView.OnDeactivateClicked += HandleDeactivate;
+        inventoryView.OnSellClicked += HandleSell;
+
+        model.OnActiveModifiersChanged += HandleActiveModifiersChanged;
+        model.OnInventoryChanged += HandleInventoryChanged;
+
+        if (scoringSystem != null)
+            scoringSystem.OnCategoryConfirmed += HandleCategoryConfirmed;
+
+        RefreshView();
+    }
+
+    private void OnDestroy()
+    {
+        if (inventoryView != null)
+        {
+            inventoryView.OnActivateClicked -= HandleActivate;
+            inventoryView.OnDeactivateClicked -= HandleDeactivate;
+            inventoryView.OnSellClicked -= HandleSell;
+        }
+
+        if (model != null)
+        {
+            model.OnActiveModifiersChanged -= HandleActiveModifiersChanged;
+            model.OnInventoryChanged -= HandleInventoryChanged;
+        }
+
+        if (scoringSystem != null)
+            scoringSystem.OnCategoryConfirmed -= HandleCategoryConfirmed;
+    }
+
+    private void HandleActivate(ModifierRuntime runtime)
+    {
+        model.TryActivate(runtime);
+    }
+
+    private void HandleDeactivate(ModifierRuntime runtime)
+    {
+        model.Deactivate(runtime);
+    }
+
+    private void HandleSell(ModifierRuntime runtime)
+    {
+        if (runtime.Data == null) return;
+
+        int sellPrice = runtime.Data.SellPrice;
+        model.RemoveModifier(runtime);
+
+        if (currencyBank != null)
+            currencyBank.Add(sellPrice);
+    }
+
+    private void HandleActiveModifiersChanged(System.Collections.Generic.List<ModifierData> activeModifiers)
+    {
+        if (scoringSystem != null)
+            scoringSystem.SetActiveModifiers(activeModifiers);
+    }
+
+    private void HandleInventoryChanged()
+    {
+        RefreshView();
+    }
+
+    private void HandleCategoryConfirmed(YachtCategory category, ScoreResult result)
+    {
+        model.ConsumeUseOnActive();
+    }
+
+    private void RefreshView()
+    {
+        if (inventoryView != null && model != null)
+            inventoryView.Refresh(model.OwnedModifiers, model.MaxActiveSlots);
+    }
+}
diff --git a/Assets/Scripts/Inventory/InventoryModel.cs b/Assets/Scripts/Inventory/InventoryModel.cs
new file mode 100644
index 0000000..4c521a6
--- /dev/null
+++ b/Assets/Scripts/Inventory/InventoryModel.cs
@@ -0,0 +1,127 @@
+using System;
+using System.Collections.Generic;
+
+public sealed class InventoryModel
+{
+    private readonly List<ModifierRuntime> ownedModifiers = new();
+    private int maxActiveSlots;
+
+    public IReadOnlyList<ModifierRuntime> OwnedModifiers => ownedModifiers;
+    public int MaxActiveSlots => maxActiveSlots;
+
+    public event Action OnInventoryChanged;
+    public event Action<List<ModifierData>> OnActiveModifiersChanged;
+
+    public InventoryModel(int maxActiveSlots = 5)
+    {
+        this.maxActiveSlots = maxActiveSlots;
+    }
+
+    public int ActiveCount
+    {
+        get
+        {
+            int count = 0;
+            for (int i = 0; i < ownedModifiers.Count; i++)
+                if (ownedModifiers[i].IsActive) count++;
+            return count;
+        }
+    }
+
+    public void SetMaxActiveSlots(int slots)
+    {
+        maxActiveSlots = slots;
+    }
+
+    public void AddModifier(ModifierData data)
+    {
+        var runtime = ModifierRuntime.Create(data);
+        ownedModifiers.Add(runtime);
+        OnInventoryChanged?.Invoke();
+    }
+
+    public void RemoveModifier(ModifierRuntime modifier)
+    {
+        if (!ownedModifiers.Contains(modifier)) return;
+
+        if (modifier.IsActive)
+        {
+            modifier.IsActive = false;
+            OnActiveModifiersChanged?.Invoke(GetActiveModifierData());
+        }
+
+        ownedModifiers.Remove(modifier);
+        OnInventoryChanged?.Invoke();
+    }
+
+    public bool TryActivate(ModifierRuntime modifier)
+    {
+        if (modifier.IsActive) return false;
+        if (!ownedModifiers.Contains(modifier)) return false;
+        if (ActiveCount >= maxActiveSlots) return false;
+
+        modifier.IsActive = true;
+        OnActiveModifiersChanged?.Invoke(GetActiveModifierData());
+        OnInventoryChanged?.Invoke();
+        return true;
+    }
+
+    public void Deactivate(ModifierRuntime modifier)
+    {
+        if (!modifier.IsActive) return;
+
+        modifier.IsActive = false;
+        OnActiveModifiersChanged?.Invoke(GetActiveModifierData());
+        OnInventoryChanged?.Invoke();
+    }
+
+    public void ConsumeUseOnActive()
+    {
+        bool changed = false;
+
+        for (int i = ownedModifiers.Count - 1; i >= 0; i--)
+        {
+            var mod = ownedModifiers[i];
+            if (!mod.IsActive) continue;
+            if (mod.Data == null) continue;
+            if (mod.Data.Durability != ModifierDurability.LimitedUses) continue;
+
+            mod.ConsumeUse();
+
+            if (mod.IsExpired)
+            {
+                ownedModifiers.RemoveAt(i);
+                changed = true;
+            }
+        }
+
+        if (changed)
+        {
+            OnActiveModifiersChanged?.Invoke(GetActiveModifierData());
+            OnInventoryChanged?.Invoke();
+        }
+    }
+
+    public List<ModifierData> GetActiveModifierData()
+    {
+        var result = new List<ModifierData>();
+        for (int i = 0; i < ownedModifiers.Count; i++)
+        {
+            if (ownedModifiers[i].IsActive && ownedModifiers[i].Data != null)
+                result.Add(ownedModifiers[i].Data);
+        }
+        return result;
+    }
+
+    public void LoadState(List<ModifierRuntime> loaded)
+    {
+        ownedModifiers.Clear();
+        if (loaded != null)
+            ownedModifiers.AddRange(loaded);
+
+        OnActiveModifiersChanged?.Invoke(GetActiveModifierData());
+        OnInventoryChanged?.Invoke();
+    }
+
+    public List<ModifierRuntime> GetAllForSave() => new(ownedModifiers);
+}
diff --git a/Assets/Scripts/Inventory/InventorySlotView.cs b/Assets/Scripts/Inventory/InventorySlotView.cs
new file mode 100644
index 0000000..64e2ef0
--- /dev/null
+++ b/Assets/Scripts/Inventory/InventorySlotView.cs
@@ -0,0 +1,78 @@
+using System;
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public sealed class InventorySlotView : MonoBehaviour
+{
+    [SerializeField] private Image iconImage;
+    [SerializeField] private TMP_Text nameText;
+    [SerializeField] private TMP_Text descriptionText;
+    [SerializeField] private TMP_Text usesText;
+    [SerializeField] private Button activateButton;
+    [SerializeField] private Button deactivateButton;
+    [SerializeField] private Button sellButton;
+    [SerializeField] private TMP_Text sellPriceText;
+    [SerializeField] private Image background;
+
+    [Header("Colors")]
+    [SerializeField] private Color activeColor = new(0.7f, 1f, 0.7f);
+    [SerializeField] private Color inactiveColor = Color.white;
+
+    private ModifierRuntime runtime;
+
+    public event Action<ModifierRuntime> OnActivateClicked;
+    public event Action<ModifierRuntime> OnDeactivateClicked;
+    public event Action<ModifierRuntime> OnSellClicked;
+
+    private void Awake()
+    {
+        if (activateButton != null)
+            activateButton.onClick.AddListener(() => OnActivateClicked?.Invoke(runtime));
+        if (deactivateButton != null)
+            deactivateButton.onClick.AddListener(() => OnDeactivateClicked?.Invoke(runtime));
+        if (sellButton != null)
+            sellButton.onClick.AddListener(() => OnSellClicked?.Invoke(runtime));
+    }
+
+    public void Setup(ModifierRuntime modifierRuntime, bool canActivateMore)
+    {
+        runtime = modifierRuntime;
+        var data = runtime.Data;
+
+        if (data == null) return;
+
+        if (nameText != null) nameText.text = data.DisplayName;
+        if (descriptionText != null) descriptionText.text = data.Description;
+        if (iconImage != null && data.Icon != null) iconImage.sprite = data.Icon;
+
+        if (usesText != null)
+        {
+            if (data.Durability == ModifierDurability.LimitedUses)
+            {
+                usesText.gameObject.SetActive(true);
+                usesText.text = $"{runtime.RemainingUses}/{data.MaxUses}";
+            }
+            else
+            {
+                usesText.gameObject.SetActive(false);
+            }
+        }
+
+        if (sellPriceText != null) sellPriceText.text = data.SellPrice.ToString();
+
+        bool isActive = runtime.IsActive;
+
+        if (activateButton != null)
+        {
+            activateButton.gameObject.SetActive(!isActive);
+            activateButton.interactable = canActivateMore;
+        }
+
+        if (deactivateButton != null)
+            deactivateButton.gameObject.SetActive(isActive);
+
+        if (background != null)
+            background.color = isActive ? activeColor : inactiveColor;
+    }
+}
diff --git a/Assets/Scripts/Inventory/InventoryView.cs b/Assets/Scripts/Inventory/InventoryView.cs
new file mode 100644
index 0000000..8468a9c
--- /dev/null
+++ b/Assets/Scripts/Inventory/InventoryView.cs
@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public sealed class InventoryView : MonoBehaviour
+{
+    [SerializeField] private Transform slotContainer;
+    [SerializeField] private InventorySlotView slotPrefab;
+    [SerializeField] private TMP_Text slotCountText;
+    [SerializeField] private Button closeButton;
+
+    private readonly List<InventorySlotView> spawnedSlots = new();
+
+    public event Action<ModifierRuntime> OnActivateClicked;
+    public event Action<ModifierRuntime> OnDeactivateClicked;
+    public event Action<ModifierRuntime> OnSellClicked;
+
+    private void Awake()
+    {
+        if (closeButton != null)
+            closeButton.onClick.AddListener(Hide);
+    }
+
+    private void OnDestroy()
+    {
+        if (closeButton != null)
+            closeButton.onClick.RemoveListener(Hide);
+    }
+
+    public void Show() => gameObject.SetActive(true);
+    public void Hide() => gameObject.SetActive(false);
+    public bool IsVisible => gameObject.activeSelf;
+
+    public void Refresh(IReadOnlyList<ModifierRuntime> owned, int maxSlots)
+    {
+        ClearSlots();
+
+        int activeCount = 0;
+
+        for (int i = 0; i < owned.Count; i++)
+        {
+            var runtime = owned[i];
+            if (runtime.IsActive) activeCount++;
+
+            var slot = Instantiate(slotPrefab, slotContainer);
+            slot.Setup(runtime, activeCount <= maxSlots);
+            slot.OnActivateClicked += HandleActivate;
+            slot.OnDeactivateClicked += HandleDeactivate;
+            slot.OnSellClicked += HandleSell;
+            spawnedSlots.Add(slot);
+        }
+
+        if (slotCountText != null)
+            slotCountText.text = $"{activeCount}/{maxSlots}";
+    }
+
+    private void ClearSlots()
+    {
+        for (int i = 0; i < spawnedSlots.Count; i++)
+        {
+            spawnedSlots[i].OnActivateClicked -= HandleActivate;
+            spawnedSlots[i].OnDeactivateClicked -= HandleDeactivate;
+            spawnedSlots[i].OnSellClicked -= HandleSell;
+            Destroy(spawnedSlots[i].gameObject);
+        }
+        spawnedSlots.Clear();
+    }
+
+    private void HandleActivate(ModifierRuntime runtime) => OnActivateClicked?.Invoke(runtime);
+    private void HandleDeactivate(ModifierRuntime runtime) => OnDeactivateClicked?.Invoke(runtime);
+    private void HandleSell(ModifierRuntime runtime) => OnSellClicked?.Invoke(runtime);
+}
diff --git a/Assets/Scripts/Modifiers/BonusForOnes.cs b/Assets/Scripts/Modifiers/BonusForOnes.cs
deleted file mode 100644
index 2db89aa..0000000
--- a/Assets/Scripts/Modifiers/BonusForOnes.cs
+++ /dev/null
@@ -1,18 +0,0 @@
-using UnityEngine;
-
-[CreateAssetMenu(fileName = "BonusForOnes", menuName = "YachtDice/Modifiers/Bonus For Ones")]
-public sealed class BonusForOnes : ScoreModifier
-{
-    [SerializeField] private int bonusPerOne = 10;
-
-    public override ModifierPhase Phase => ModifierPhase.Additive;
-
-    public override void Apply(ref ScoreResult result)
-    {
-        int count = 0;
-        for (int i = 0; i < result.DiceValues.Length; i++)
-            if (result.DiceValues[i] == 1) count++;
-
-        result.FlatBonus += bonusPerOne * count;
-    }
-}
diff --git a/Assets/Scripts/Modifiers/ModifierData.cs b/Assets/Scripts/Modifiers/ModifierData.cs
new file mode 100644
index 0000000..05b9a0c
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierData.cs
@@ -0,0 +1,88 @@
+using UnityEngine;
+
+[CreateAssetMenu(fileName = "NewModifier", menuName = "YachtDice/Modifier Data")]
+public sealed class ModifierData : ScriptableObject
+{
+    [SerializeField] private string id;
+    [SerializeField] private string displayName;
+    [SerializeField] [TextArea] private string description;
+    [SerializeField] private ModifierRarity rarity;
+    [SerializeField] private int shopPrice;
+    [SerializeField] private int sellPrice;
+    [SerializeField] private Sprite icon;
+
+    [Header("Effect")]
+    [SerializeField] private ModifierScope scope;
+    [SerializeField] private ModifierEffectType effectType;
+    [SerializeField] private ModifierTarget target;
+    [SerializeField] private float effectValue;
+
+    [Header("Durability")]
+    [SerializeField] private ModifierDurability durability;
+    [SerializeField] private int maxUses;
+
+    public string Id => id;
+    public string DisplayName => displayName;
+    public string Description => description;
+    public ModifierRarity Rarity => rarity;
+    public int ShopPrice => shopPrice;
+    public int SellPrice => sellPrice;
+    public Sprite Icon => icon;
+    public ModifierScope Scope => scope;
+    public ModifierEffectType EffectType => effectType;
+    public ModifierTarget Target => target;
+    public float EffectValue => effectValue;
+    public ModifierDurability Durability => durability;
+    public int MaxUses => maxUses;
+
+    public bool IsAdditive =>
+        effectType == ModifierEffectType.AddPerDieValue ||
+        effectType == ModifierEffectType.AddFlatToFinalScore;
+
+    public bool IsMultiplicative =>
+        effectType == ModifierEffectType.MultiplyPerDieValue ||
+        effectType == ModifierEffectType.MultiplyFinalScore;
+
+    public bool IsCategoryLevel =>
+        effectType == ModifierEffectType.AddPerDieValue ||
+        effectType == ModifierEffectType.MultiplyPerDieValue;
+
+    public bool IsFinalScoreLevel =>
+        effectType == ModifierEffectType.AddFlatToFinalScore ||
+        effectType == ModifierEffectType.MultiplyFinalScore;
+
+#if UNITY_EDITOR
+    public static ModifierData CreateForTest(
+        string id,
+        ModifierScope scope,
+        ModifierEffectType effectType,
+        float effectValue,
+        int dieValue = 0,
+        YachtCategory targetCategory = YachtCategory.Ones,
+        bool hasCategoryFilter = false,
+        ModifierDurability durability = ModifierDurability.Permanent,
+        int maxUses = 0,
+        int shopPrice = 100,
+        int sellPrice = 50)
+    {
+        var data = CreateInstance<ModifierData>();
+        data.id = id;
+        data.displayName = id;
+        data.description = id;
+        data.scope = scope;
+        data.effectType = effectType;
+        data.effectValue = effectValue;
+        data.target = new ModifierTarget
+        {
+            DieValue = dieValue,
+            TargetCategory = targetCategory,
+            HasCategoryFilter = hasCategoryFilter
+        };
+        data.durability = durability;
+        data.maxUses = maxUses;
+        data.shopPrice = shopPrice;
+        data.sellPrice = sellPrice;
+        return data;
+    }
+#endif
+}
diff --git a/Assets/Scripts/Modifiers/ModifierEffect.cs b/Assets/Scripts/Modifiers/ModifierEffect.cs
new file mode 100644
index 0000000..4f3b0aa
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierEffect.cs
@@ -0,0 +1,55 @@
+using System.Collections.Generic;
+
+public delegate void ModifierHandler(ModifierData data, ref ScoreResult result);
+
+public static class ModifierEffect
+{
+    private static readonly Dictionary<ModifierEffectType, ModifierHandler> Handlers = new()
+    {
+        { ModifierEffectType.AddPerDieValue, ApplyAddPerDieValue },
+        { ModifierEffectType.AddFlatToFinalScore, ApplyAddFlat },
+        { ModifierEffectType.MultiplyPerDieValue, ApplyMultiplyPerDieValue },
+        { ModifierEffectType.MultiplyFinalScore, ApplyMultiplyFinal }
+    };
+
+    public static void Apply(ModifierData data, ref ScoreResult result)
+    {
+        if (Handlers.TryGetValue(data.EffectType, out var handler))
+            handler(data, ref result);
+    }
+
+    private static void ApplyAddPerDieValue(ModifierData data, ref ScoreResult result)
+    {
+        int targetValue = data.Target.DieValue;
+        int count = 0;
+
+        for (int i = 0; i < result.DiceValues.Length; i++)
+        {
+            if (targetValue == 0 || result.DiceValues[i] == targetValue)
+                count++;
+        }
+
+        result.FlatBonus += (int)(data.EffectValue * count);
+    }
+
+    private static void ApplyAddFlat(ModifierData data, ref ScoreResult result)
+    {
+        result.FlatBonus += (int)data.EffectValue;
+    }
+
+    private static void ApplyMultiplyPerDieValue(ModifierData data, ref ScoreResult result)
+    {
+        int targetValue = data.Target.DieValue;
+
+        for (int i = 0; i < result.DiceValues.Length; i++)
+        {
+            if (targetValue == 0 || result.DiceValues[i] == targetValue)
+                result.Multiplier *= data.EffectValue;
+        }
+    }
+
+    private static void ApplyMultiplyFinal(ModifierData data, ref ScoreResult result)
+    {
+        result.Multiplier *= data.EffectValue;
+    }
+}
diff --git a/Assets/Scripts/Modifiers/ModifierEnums.cs b/Assets/Scripts/Modifiers/ModifierEnums.cs
new file mode 100644
index 0000000..d4db390
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierEnums.cs
@@ -0,0 +1,27 @@
+public enum ModifierScope
+{
+    SelectedCategory,
+    AnyCategoryClosed
+}
+
+public enum ModifierEffectType
+{
+    AddPerDieValue,
+    AddFlatToFinalScore,
+    MultiplyPerDieValue,
+    MultiplyFinalScore
+}
+
+public enum ModifierDurability
+{
+    Permanent,
+    LimitedUses
+}
+
+public enum ModifierRarity
+{
+    Common,
+    Uncommon,
+    Rare,
+    Epic
+}
diff --git a/Assets/Scripts/Modifiers/ModifierPipeline.cs b/Assets/Scripts/Modifiers/ModifierPipeline.cs
new file mode 100644
index 0000000..673f2b2
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierPipeline.cs
@@ -0,0 +1,62 @@
+using System.Collections.Generic;
+
+public static class ModifierPipeline
+{
+    // Application order (explicit):
+    //   1. Category-level additive   (AddPerDieValue)
+    //   2. Category-level multiplicative (MultiplyPerDieValue)
+    //   3. Final-score additive      (AddFlatToFinalScore)
+    //   4. Final-score multiplicative (MultiplyFinalScore)
+
+    public static void Apply(
+        IReadOnlyList<ModifierData> activeModifiers,
+        ref ScoreResult result,
+        ModifierScope currentScope)
+    {
+        if (activeModifiers == null) return;
+
+        // Pass 1: Category-level additive
+        for (int i = 0; i < activeModifiers.Count; i++)
+        {
+            var mod = activeModifiers[i];
+            if (!ShouldApply(mod, ref result, currentScope)) continue;
+            if (mod.IsCategoryLevel && mod.IsAdditive)
+                ModifierEffect.Apply(mod, ref result);
+        }
+
+        // Pass 2: Category-level multiplicative
+        for (int i = 0; i < activeModifiers.Count; i++)
+        {
+            var mod = activeModifiers[i];
+            if (!ShouldApply(mod, ref result, currentScope)) continue;
+            if (mod.IsCategoryLevel && mod.IsMultiplicative)
+                ModifierEffect.Apply(mod, ref result);
+        }
+
+        // Pass 3: Final-score additive
+        for (int i = 0; i < activeModifiers.Count; i++)
+        {
+            var mod = activeModifiers[i];
+            if (!ShouldApply(mod, ref result, currentScope)) continue;
+            if (mod.IsFinalScoreLevel && mod.IsAdditive)
+                ModifierEffect.Apply(mod, ref result);
+        }
+
+        // Pass 4: Final-score multiplicative
+        for (int i = 0; i < activeModifiers.Count; i++)
+        {
+            var mod = activeModifiers[i];
+            if (!ShouldApply(mod, ref result, currentScope)) continue;
+            if (mod.IsFinalScoreLevel && mod.IsMultiplicative)
+                ModifierEffect.Apply(mod, ref result);
+        }
+    }
+
+    private static bool ShouldApply(ModifierData mod, ref ScoreResult result, ModifierScope currentScope)
+    {
+        if (mod == null) return false;
+        if (mod.Scope != currentScope) return false;
+        if (mod.Target.HasCategoryFilter && mod.Target.TargetCategory != result.Category) return false;
+        return true;
+    }
+}
diff --git a/Assets/Scripts/Modifiers/ModifierRuntime.cs b/Assets/Scripts/Modifiers/ModifierRuntime.cs
new file mode 100644
index 0000000..bfb0be6
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierRuntime.cs
@@ -0,0 +1,34 @@
+using System;
+
+[Serializable]
+public sealed class ModifierRuntime
+{
+    public string ModifierId;
+    public bool IsActive;
+    public int RemainingUses;
+
+    [NonSerialized] public ModifierData Data;
+
+    public bool IsExpired => Data != null &&
+                             Data.Durability == ModifierDurability.LimitedUses &&
+                             RemainingUses <= 0;
+
+    public void ConsumeUse()
+    {
+        if (Data == null) return;
+        if (Data.Durability != ModifierDurability.LimitedUses) return;
+
+        RemainingUses--;
+    }
+
+    public static ModifierRuntime Create(ModifierData data)
+    {
+        return new ModifierRuntime
+        {
+            ModifierId = data.Id,
+            IsActive = false,
+            RemainingUses = data.Durability == ModifierDurability.LimitedUses ? data.MaxUses : -1,
+            Data = data
+        };
+    }
+}
diff --git a/Assets/Scripts/Modifiers/ModifierTarget.cs b/Assets/Scripts/Modifiers/ModifierTarget.cs
new file mode 100644
index 0000000..a64eafb
--- /dev/null
+++ b/Assets/Scripts/Modifiers/ModifierTarget.cs
@@ -0,0 +1,16 @@
+using System;
+using UnityEngine;
+
+[Serializable]
+public struct ModifierTarget
+{
+    [Tooltip("Die face value (1-6). 0 = any/all dice.")]
+    [Range(0, 6)]
+    public int DieValue;
+
+    [Tooltip("Category this modifier targets.")]
+    public YachtCategory TargetCategory;
+
+    [Tooltip("If true, TargetCategory is used as a filter.")]
+    public bool HasCategoryFilter;
+}
diff --git a/Assets/Scripts/Modifiers/MultiplierForSixes.cs b/Assets/Scripts/Modifiers/MultiplierForSixes.cs
deleted file mode 100644
index 4fc33cf..0000000
--- a/Assets/Scripts/Modifiers/MultiplierForSixes.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using UnityEngine;
-
-[CreateAssetMenu(fileName = "MultiplierForSixes", menuName = "YachtDice/Modifiers/Multiplier For Sixes")]
-public sealed class MultiplierForSixes : ScoreModifier
-{
-    [SerializeField] private float multiplierPerSix = 6f;
-
-    public override ModifierPhase Phase => ModifierPhase.Multiplicative;
-
-    public override void Apply(ref ScoreResult result)
-    {
-        for (int i = 0; i < result.DiceValues.Length; i++)
-            if (result.DiceValues[i] == 6)
-                result.Multiplier *= multiplierPerSix;
-    }
-}
diff --git a/Assets/Scripts/Modifiers/ScoreModifier.cs b/Assets/Scripts/Modifiers/ScoreModifier.cs
deleted file mode 100644
index 615cc19..0000000
--- a/Assets/Scripts/Modifiers/ScoreModifier.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using UnityEngine;
-
-public abstract class ScoreModifier : ScriptableObject
-{
-    public enum ModifierPhase
-    {
-        Additive,
-        Multiplicative
-    }
-
-    [SerializeField] private string displayName;
-    [SerializeField] [TextArea] private string description;
-
-    public string DisplayName => displayName;
-    public string Description => description;
-
-    public abstract ModifierPhase Phase { get; }
-    public abstract void Apply(ref ScoreResult result);
-}
diff --git a/Assets/Scripts/Persistence/SaveData.cs b/Assets/Scripts/Persistence/SaveData.cs
new file mode 100644
index 0000000..22b18f8
--- /dev/null
+++ b/Assets/Scripts/Persistence/SaveData.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+
+[Serializable]
+public sealed class SaveData
+{
+    public int Version = 1;
+    public int Currency;
+    public List<ModifierSaveEntry> OwnedModifiers = new();
+}
+
+[Serializable]
+public sealed class ModifierSaveEntry
+{
+    public string ModifierId;
+    public bool IsActive;
+    public int RemainingUses;
+}
diff --git a/Assets/Scripts/Persistence/SaveSystem.cs b/Assets/Scripts/Persistence/SaveSystem.cs
new file mode 100644
index 0000000..e661639
--- /dev/null
+++ b/Assets/Scripts/Persistence/SaveSystem.cs
@@ -0,0 +1,42 @@
+using Newtonsoft.Json;
+using UnityEngine;
+
+public static class SaveSystem
+{
+    private const string SaveKey = "YachtDice_SaveData";
+
+    public static void Save(SaveData data)
+    {
+        string json = JsonConvert.SerializeObject(data, Formatting.Indented);
+        PlayerPrefs.SetString(SaveKey, json);
+        PlayerPrefs.Save();
+    }
+
+    public static SaveData Load()
+    {
+        if (!PlayerPrefs.HasKey(SaveKey))
+            return new SaveData();
+
+        string json = PlayerPrefs.GetString(SaveKey);
+
+        try
+        {
+            return JsonConvert.DeserializeObject<SaveData>(json) ?? new SaveData();
+        }
+        catch (JsonException e)
+        {
+            Debug.LogWarning($"Failed to deserialize save data, returning default: {e.Message}");
+            return new SaveData();
+        }
+    }
+
+    public static void Delete()
+    {
+        PlayerPrefs.DeleteKey(SaveKey);
+    }
+
+    public static bool HasSave()
+    {
+        return PlayerPrefs.HasKey(SaveKey);
+    }
+}
diff --git a/Assets/Scripts/Scoring/ScoringSystem.cs b/Assets/Scripts/Scoring/ScoringSystem.cs
index 97fb5d1..e52126c 100644
--- a/Assets/Scripts/Scoring/ScoringSystem.cs
+++ b/Assets/Scripts/Scoring/ScoringSystem.cs
@@ -4,14 +4,13 @@ using UnityEngine;
 
 public sealed class ScoringSystem : MonoBehaviour
 {
-    [Header("Modifiers")]
-    [SerializeField] private List<ScoreModifier> activeModifiers = new();
-
     public event Action<YachtCategory, int> OnCategoryScored;
     public event Action<int> OnAllCategoriesScored;
+    public event Action<YachtCategory, ScoreResult> OnCategoryConfirmed;
 
     private readonly Dictionary<YachtCategory, int> scorecard = new();
     private readonly HashSet<YachtCategory> usedCategories = new();
+    private List<ModifierData> activeModifierData = new();
 
     public bool IsCategoryUsed(YachtCategory category) => usedCategories.Contains(category);
 
@@ -36,24 +35,20 @@ public sealed class ScoringSystem : MonoBehaviour
 
     public bool IsComplete => CategoriesFilledCount >= TotalCategoryCount;
 
-    public void AddModifier(ScoreModifier modifier)
+    public void SetActiveModifiers(List<ModifierData> modifiers)
     {
-        if (modifier != null && !activeModifiers.Contains(modifier))
-            activeModifiers.Add(modifier);
+        activeModifierData = modifiers ?? new List<ModifierData>();
     }
 
-    public void RemoveModifier(ScoreModifier modifier)
-    {
-        activeModifiers.Remove(modifier);
-    }
-
-    public IReadOnlyList<ScoreModifier> ActiveModifiers => activeModifiers;
+    public IReadOnlyList<ModifierData> ActiveModifiers => activeModifierData;
 
     public ScoreResult PreviewScore(int[] diceValues, YachtCategory category)
     {
         int baseScore = CategoryScorer.Calculate(diceValues, category);
         ScoreResult result = ScoreResult.Create(baseScore, diceValues, category);
-        ApplyModifiers(ref result);
+
+        ModifierPipeline.Apply(activeModifierData, ref result, ModifierScope.SelectedCategory);
+
         return result;
     }
 
@@ -62,13 +57,18 @@ public sealed class ScoringSystem : MonoBehaviour
         if (usedCategories.Contains(category))
             throw new InvalidOperationException($"Category {category} has already been scored.");
 
-        ScoreResult result = PreviewScore(diceValues, category);
+        int baseScore = CategoryScorer.Calculate(diceValues, category);
+        ScoreResult result = ScoreResult.Create(baseScore, diceValues, category);
+
+        ModifierPipeline.Apply(activeModifierData, ref result, ModifierScope.SelectedCategory);
+        ModifierPipeline.Apply(activeModifierData, ref result, ModifierScope.AnyCategoryClosed);
 
         int finalScore = result.FinalScore;
         scorecard[category] = finalScore;
         usedCategories.Add(category);
 
         OnCategoryScored?.Invoke(category, finalScore);
+        OnCategoryConfirmed?.Invoke(category, result);
 
         if (IsComplete)
             OnAllCategoriesScored?.Invoke(TotalScore);
@@ -76,25 +76,6 @@ public sealed class ScoringSystem : MonoBehaviour
         return result;
     }
 
-    private void ApplyModifiers(ref ScoreResult result)
-    {
-        // Pass 1: Additive
-        for (int i = 0; i < activeModifiers.Count; i++)
-        {
-            if (activeModifiers[i] == null) continue;
-            if (activeModifiers[i].Phase == ScoreModifier.ModifierPhase.Additive)
-                activeModifiers[i].Apply(ref result);
-        }
-
-        // Pass 2: Multiplicative
-        for (int i = 0; i < activeModifiers.Count; i++)
-        {
-            if (activeModifiers[i] == null) continue;
-            if (activeModifiers[i].Phase == ScoreModifier.ModifierPhase.Multiplicative)
-                activeModifiers[i].Apply(ref result);
-        }
-    }
-
     public void ResetScorecard()
     {
         scorecard.Clear();
diff --git a/Assets/Scripts/Shop/ShopCatalog.cs b/Assets/Scripts/Shop/ShopCatalog.cs
new file mode 100644
index 0000000..8916c51
--- /dev/null
+++ b/Assets/Scripts/Shop/ShopCatalog.cs
@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+[CreateAssetMenu(fileName = "ShopCatalog", menuName = "YachtDice/Shop Catalog")]
+public sealed class ShopCatalog : ScriptableObject
+{
+    [SerializeField] private List<ModifierData> availableModifiers = new();
+
+    public IReadOnlyList<ModifierData> AvailableModifiers => availableModifiers;
+
+    public ModifierData FindById(string id)
+    {
+        for (int i = 0; i < availableModifiers.Count; i++)
+        {
+            if (availableModifiers[i] != null && availableModifiers[i].Id == id)
+                return availableModifiers[i];
+        }
+        return null;
+    }
+}
diff --git a/Assets/Scripts/Shop/ShopController.cs b/Assets/Scripts/Shop/ShopController.cs
new file mode 100644
index 0000000..4680fbc
--- /dev/null
+++ b/Assets/Scripts/Shop/ShopController.cs
@@ -0,0 +1,55 @@
+using UnityEngine;
+
+public sealed class ShopController : MonoBehaviour
+{
+    [SerializeField] private ShopCatalog catalog;
+    [SerializeField] private ShopView shopView;
+    [SerializeField] private CurrencyBank currencyBank;
+
+    private ShopModel model;
+
+    public ShopCatalog Catalog => catalog;
+
+    public void Initialize(ShopModel shopModel)
+    {
+        model = shopModel;
+
+        shopView.OnBuyClicked += HandleBuyClicked;
+
+        if (currencyBank != null)
+            currencyBank.OnBalanceChanged += HandleCurrencyChanged;
+
+        model.OnItemPurchased += HandleItemPurchased;
+
+        shopView.Populate(catalog.AvailableModifiers, model);
+        shopView.UpdateCurrencyDisplay(currencyBank != null ? currencyBank.Balance : 0);
+    }
+
+    private void OnDestroy()
+    {
+        if (shopView != null)
+            shopView.OnBuyClicked -= HandleBuyClicked;
+
+        if (currencyBank != null)
+            currencyBank.OnBalanceChanged -= HandleCurrencyChanged;
+
+        if (model != null)
+            model.OnItemPurchased -= HandleItemPurchased;
+    }
+
+    private void HandleBuyClicked(ModifierData data)
+    {
+        model.TryPurchase(data);
+    }
+
+    private void HandleCurrencyChanged(int newBalance)
+    {
+        shopView.UpdateCurrencyDisplay(newBalance);
+        shopView.RefreshStates(catalog.AvailableModifiers, model);
+    }
+
+    private void HandleItemPurchased(ModifierData data)
+    {
+        shopView.RefreshStates(catalog.AvailableModifiers, model);
+    }
+}
diff --git a/Assets/Scripts/Shop/ShopItemView.cs b/Assets/Scripts/Shop/ShopItemView.cs
new file mode 100644
index 0000000..db0ecc5
--- /dev/null
+++ b/Assets/Scripts/Shop/ShopItemView.cs
@@ -0,0 +1,87 @@
+using System;
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public sealed class ShopItemView : MonoBehaviour
+{
+    [SerializeField] private Image iconImage;
+    [SerializeField] private TMP_Text nameText;
+    [SerializeField] private TMP_Text descriptionText;
+    [SerializeField] private TMP_Text priceText;
+    [SerializeField] private TMP_Text rarityText;
+    [SerializeField] private Button buyButton;
+    [SerializeField] private TMP_Text buyButtonText;
+    [SerializeField] private Image background;
+
+    [Header("Rarity Colors")]
+    [SerializeField] private Color commonColor = Color.white;
+    [SerializeField] private Color uncommonColor = new(0.4f, 0.8f, 0.4f);
+    [SerializeField] private Color rareColor = new(0.4f, 0.6f, 1f);
+    [SerializeField] private Color epicColor = new(0.8f, 0.4f, 1f);
+
+    private ModifierData data;
+
+    public event Action<ModifierData> OnBuyClicked;
+
+    private void Awake()
+    {
+        if (buyButton != null)
+            buyButton.onClick.AddListener(() => OnBuyClicked?.Invoke(data));
+    }
+
+    public void Setup(ModifierData modifierData, ShopItemState state)
+    {
+        data = modifierData;
+
+        if (nameText != null) nameText.text = data.DisplayName;
+        if (descriptionText != null) descriptionText.text = data.Description;
+        if (priceText != null) priceText.text = data.ShopPrice.ToString();
+        if (iconImage != null && data.Icon != null) iconImage.sprite = data.Icon;
+
+        if (rarityText != null)
+        {
+            rarityText.text = data.Rarity.ToString();
+            rarityText.color = GetRarityColor(data.Rarity);
+        }
+
+        SetState(state);
+    }
+
+    public void SetState(ShopItemState state)
+    {
+        if (buyButton == null) return;
+
+        switch (state)
+        {
+            case ShopItemState.Available:
+                buyButton.interactable = true;
+                if (buyButtonText != null) buyButtonText.text = "Buy";
+                break;
+            case ShopItemState.RepurchaseAvailable:
+                buyButton.interactable = true;
+                if (buyButtonText != null) buyButtonText.text = "Buy";
+                break;
+            case ShopItemState.TooExpensive:
+                buyButton.interactable = false;
+                if (buyButtonText != null) buyButtonText.text = "Buy";
+                break;
+            case ShopItemState.Owned:
+                buyButton.interactable = false;
+                if (buyButtonText != null) buyButtonText.text = "Owned";
+                break;
+        }
+    }
+
+    private Color GetRarityColor(ModifierRarity rarity)
+    {
+        return rarity switch
+        {
+            ModifierRarity.Common => commonColor,
+            ModifierRarity.Uncommon => uncommonColor,
+            ModifierRarity.Rare => rareColor,
+            ModifierRarity.Epic => epicColor,
+            _ => commonColor
+        };
+    }
+}
diff --git a/Assets/Scripts/Shop/ShopModel.cs b/Assets/Scripts/Shop/ShopModel.cs
new file mode 100644
index 0000000..676e217
--- /dev/null
+++ b/Assets/Scripts/Shop/ShopModel.cs
@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+
+public sealed class ShopModel
+{
+    private readonly CurrencyBank currencyBank;
+    private readonly InventoryModel inventoryModel;
+    private readonly HashSet<string> purchasedPermanentIds = new();
+
+    public event Action<ModifierData> OnItemPurchased;
+
+    public ShopModel(CurrencyBank currencyBank, InventoryModel inventoryModel)
+    {
+        this.currencyBank = currencyBank;
+        this.inventoryModel = inventoryModel;
+    }
+
+    public bool CanPurchase(ModifierData modifier)
+    {
+        if (modifier == null) return false;
+        if (!currencyBank.CanAfford(modifier.ShopPrice)) return false;
+
+        if (modifier.Durability == ModifierDurability.Permanent &&
+            purchasedPermanentIds.Contains(modifier.Id))
+            return false;
+
+        return true;
+    }
+
+    public bool TryPurchase(ModifierData modifier)
+    {
+        if (!CanPurchase(modifier)) return false;
+
+        if (!currencyBank.Spend(modifier.ShopPrice)) return false;
+
+        if (modifier.Durability == ModifierDurability.Permanent)
+            purchasedPermanentIds.Add(modifier.Id);
+
+        inventoryModel.AddModifier(modifier);
+        OnItemPurchased?.Invoke(modifier);
+        return true;
+    }
+
+    public bool IsPermanentOwned(string modifierId) => purchasedPermanentIds.Contains(modifierId);
+
+    public ShopItemState GetItemState(ModifierData modifier)
+    {
+        if (modifier == null) return ShopItemState.TooExpensive;
+
+        if (modifier.Durability == ModifierDurability.Permanent &&
+            purchasedPermanentIds.Contains(modifier.Id))
+            return ShopItemState.Owned;
+
+        if (!currencyBank.CanAfford(modifier.ShopPrice))
+            return ShopItemState.TooExpensive;
+
+        return modifier.Durability == ModifierDurability.LimitedUses
+            ? ShopItemState.RepurchaseAvailable
+            : ShopItemState.Available;
+    }
+
+    public void LoadPurchasedPermanentIds(IEnumerable<string> ids)
+    {
+        purchasedPermanentIds.Clear();
+        if (ids != null)
+            foreach (var id in ids) purchasedPermanentIds.Add(id);
+    }
+
+    public HashSet<string> GetPurchasedPermanentIds() => new(purchasedPermanentIds);
+}
+
+public enum ShopItemState
+{
+    Available,
+    TooExpensive,
+    Owned,
+    RepurchaseAvailable
+}
diff --git a/Assets/Scripts/Shop/ShopView.cs b/Assets/Scripts/Shop/ShopView.cs
new file mode 100644
index 0000000..25e8394
--- /dev/null
+++ b/Assets/Scripts/Shop/ShopView.cs
@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public sealed class ShopView : MonoBehaviour
+{
+    [SerializeField] private Transform itemContainer;
+    [SerializeField] private ShopItemView itemPrefab;
+    [SerializeField] private TMP_Text currencyText;
+    [SerializeField] private Button closeButton;
+
+    private readonly List<ShopItemView> spawnedItems = new();
+
+    public event Action<ModifierData> OnBuyClicked;
+
+    private void Awake()
+    {
+        if (closeButton != null)
+            closeButton.onClick.AddListener(Hide);
+    }
+
+    private void OnDestroy()
+    {
+        if (closeButton != null)
+            closeButton.onClick.RemoveListener(Hide);
+    }
+
+    public void Show() => gameObject.SetActive(true);
+    public void Hide() => gameObject.SetActive(false);
+    public bool IsVisible => gameObject.activeSelf;
+
+    public void Populate(IReadOnlyList<ModifierData> catalog, ShopModel model)
+    {
+        ClearItems();
+
+        for (int i = 0; i < catalog.Count; i++)
+        {
+            var data = catalog[i];
+            if (data == null) continue;
+
+            var item = Instantiate(itemPrefab, itemContainer);
+            var state = model.GetItemState(data);
+            item.Setup(data, state);
+            item.OnBuyClicked += HandleBuy;
+            spawnedItems.Add(item);
+        }
+    }
+
+    public void RefreshStates(IReadOnlyList<ModifierData> catalog, ShopModel model)
+    {
+        for (int i = 0; i < spawnedItems.Count && i < catalog.Count; i++)
+        {
+            var state = model.GetItemState(catalog[i]);
+            spawnedItems[i].SetState(state);
+        }
+    }
+
+    public void UpdateCurrencyDisplay(int currency)
+    {
+        if (currencyText != null)
+            currencyText.text = currency.ToString();
+    }
+
+    private void ClearItems()
+    {
+        for (int i = 0; i < spawnedItems.Count; i++)
+        {
+            spawnedItems[i].OnBuyClicked -= HandleBuy;
+            Destroy(spawnedItems[i].gameObject);
+        }
+        spawnedItems.Clear();
+    }
+
+    private void HandleBuy(ModifierData data) => OnBuyClicked?.Invoke(data);
+}
diff --git a/Assets/Scripts/Tests/Editor/InventoryModelTests.cs b/Assets/Scripts/Tests/Editor/InventoryModelTests.cs
new file mode 100644
index 0000000..9eeb256
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/InventoryModelTests.cs
@@ -0,0 +1,155 @@
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class InventoryModelTests
+{
+    private InventoryModel inventory;
+
+    [SetUp]
+    public void SetUp()
+    {
+        inventory = new InventoryModel(3);
+    }
+
+    private ModifierData CreateTestData(string id = "test",
+        ModifierDurability durability = ModifierDurability.Permanent, int maxUses = 0)
+    {
+        return ModifierData.CreateForTest(id, ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f,
+            durability: durability, maxUses: maxUses);
+    }
+
+    [Test]
+    public void AddModifier_IncreasesCount()
+    {
+        inventory.AddModifier(CreateTestData());
+
+        Assert.AreEqual(1, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void TryActivate_SucceedsWithinSlotLimit()
+    {
+        inventory.AddModifier(CreateTestData("a"));
+        var mod = inventory.OwnedModifiers[0];
+
+        bool result = inventory.TryActivate(mod);
+
+        Assert.IsTrue(result);
+        Assert.IsTrue(mod.IsActive);
+        Assert.AreEqual(1, inventory.ActiveCount);
+    }
+
+    [Test]
+    public void TryActivate_FailsWhenSlotsFull()
+    {
+        for (int i = 0; i < 3; i++)
+        {
+            inventory.AddModifier(CreateTestData($"m{i}"));
+            inventory.TryActivate(inventory.OwnedModifiers[i]);
+        }
+
+        inventory.AddModifier(CreateTestData("extra"));
+        var extra = inventory.OwnedModifiers[3];
+        bool result = inventory.TryActivate(extra);
+
+        Assert.IsFalse(result);
+        Assert.IsFalse(extra.IsActive);
+        Assert.AreEqual(3, inventory.ActiveCount);
+    }
+
+    [Test]
+    public void Deactivate_FreesSlot()
+    {
+        inventory.AddModifier(CreateTestData());
+        var mod = inventory.OwnedModifiers[0];
+        inventory.TryActivate(mod);
+
+        inventory.Deactivate(mod);
+
+        Assert.IsFalse(mod.IsActive);
+        Assert.AreEqual(0, inventory.ActiveCount);
+    }
+
+    [Test]
+    public void RemoveModifier_DeactivatesAndRemoves()
+    {
+        inventory.AddModifier(CreateTestData());
+        var mod = inventory.OwnedModifiers[0];
+        inventory.TryActivate(mod);
+
+        inventory.RemoveModifier(mod);
+
+        Assert.AreEqual(0, inventory.OwnedModifiers.Count);
+        Assert.AreEqual(0, inventory.ActiveCount);
+    }
+
+    [Test]
+    public void ConsumeUseOnActive_DecrementsUses()
+    {
+        inventory.AddModifier(CreateTestData("ltd", ModifierDurability.LimitedUses, 3));
+        var mod = inventory.OwnedModifiers[0];
+        inventory.TryActivate(mod);
+
+        inventory.ConsumeUseOnActive();
+
+        Assert.AreEqual(2, mod.RemainingUses);
+    }
+
+    [Test]
+    public void ConsumeUseOnActive_RemovesExpired()
+    {
+        inventory.AddModifier(CreateTestData("ltd", ModifierDurability.LimitedUses, 1));
+        var mod = inventory.OwnedModifiers[0];
+        inventory.TryActivate(mod);
+
+        inventory.ConsumeUseOnActive();
+
+        Assert.AreEqual(0, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void ConsumeUseOnActive_IgnoresPermanent()
+    {
+        inventory.AddModifier(CreateTestData("perm", ModifierDurability.Permanent));
+        var mod = inventory.OwnedModifiers[0];
+        inventory.TryActivate(mod);
+
+        inventory.ConsumeUseOnActive();
+
+        Assert.AreEqual(1, inventory.OwnedModifiers.Count);
+        Assert.IsTrue(mod.IsActive);
+    }
+
+    [Test]
+    public void GetActiveModifierData_ReturnsOnlyActive()
+    {
+        inventory.AddModifier(CreateTestData("a"));
+        inventory.AddModifier(CreateTestData("b"));
+        inventory.TryActivate(inventory.OwnedModifiers[0]);
+
+        var active = inventory.GetActiveModifierData();
+
+        Assert.AreEqual(1, active.Count);
+    }
+
+    [Test]
+    public void SetMaxActiveSlots_AllowsExpansion()
+    {
+        inventory.SetMaxActiveSlots(10);
+
+        Assert.AreEqual(10, inventory.MaxActiveSlots);
+    }
+
+    [Test]
+    public void OnActiveModifiersChanged_FiredOnActivate()
+    {
+        bool fired = false;
+        inventory.OnActiveModifiersChanged += _ => fired = true;
+        inventory.AddModifier(CreateTestData());
+
+        inventory.TryActivate(inventory.OwnedModifiers[0]);
+
+        Assert.IsTrue(fired);
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/ModifierEffectTests.cs b/Assets/Scripts/Tests/Editor/ModifierEffectTests.cs
new file mode 100644
index 0000000..fe26e77
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/ModifierEffectTests.cs
@@ -0,0 +1,89 @@
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class ModifierEffectTests
+{
+    private static ModifierData CreateData(
+        ModifierEffectType effectType, float effectValue,
+        int dieValue = 0, ModifierScope scope = ModifierScope.SelectedCategory)
+    {
+        return ModifierData.CreateForTest("test", scope, effectType, effectValue, dieValue);
+    }
+
+    [Test]
+    public void AddPerDieValue_CountsMatchingDice()
+    {
+        var data = CreateData(ModifierEffectType.AddPerDieValue, 10f, dieValue: 1);
+        var result = ScoreResult.Create(5, new[] { 1, 1, 3, 4, 1 }, YachtCategory.Ones);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(30, result.FlatBonus);
+    }
+
+    [Test]
+    public void AddPerDieValue_ZeroTarget_CountsAllDice()
+    {
+        var data = CreateData(ModifierEffectType.AddPerDieValue, 2f, dieValue: 0);
+        var result = ScoreResult.Create(10, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(10, result.FlatBonus);
+    }
+
+    [Test]
+    public void AddPerDieValue_NoMatches_ZeroBonus()
+    {
+        var data = CreateData(ModifierEffectType.AddPerDieValue, 10f, dieValue: 6);
+        var result = ScoreResult.Create(5, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(0, result.FlatBonus);
+    }
+
+    [Test]
+    public void AddFlatToFinalScore_AddsFlat()
+    {
+        var data = CreateData(ModifierEffectType.AddFlatToFinalScore, 15f);
+        var result = ScoreResult.Create(25, new[] { 3, 3, 2, 2, 2 }, YachtCategory.FullHouse);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(15, result.FlatBonus);
+    }
+
+    [Test]
+    public void MultiplyPerDieValue_MultipliesPerMatch()
+    {
+        var data = CreateData(ModifierEffectType.MultiplyPerDieValue, 2f, dieValue: 6);
+        var result = ScoreResult.Create(18, new[] { 6, 6, 6, 1, 2 }, YachtCategory.Sixes);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(8f, result.Multiplier); // 1 * 2 * 2 * 2 = 8
+    }
+
+    [Test]
+    public void MultiplyPerDieValue_NoMatches_MultiplierUnchanged()
+    {
+        var data = CreateData(ModifierEffectType.MultiplyPerDieValue, 3f, dieValue: 6);
+        var result = ScoreResult.Create(10, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(1f, result.Multiplier);
+    }
+
+    [Test]
+    public void MultiplyFinalScore_MultipliesOnce()
+    {
+        var data = CreateData(ModifierEffectType.MultiplyFinalScore, 1.5f);
+        var result = ScoreResult.Create(50, new[] { 6, 6, 6, 6, 6 }, YachtCategory.Yacht);
+
+        ModifierEffect.Apply(data, ref result);
+
+        Assert.AreEqual(1.5f, result.Multiplier, 0.001f);
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/ModifierPipelineTests.cs b/Assets/Scripts/Tests/Editor/ModifierPipelineTests.cs
new file mode 100644
index 0000000..2658ba6
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/ModifierPipelineTests.cs
@@ -0,0 +1,136 @@
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class ModifierPipelineTests
+{
+    [Test]
+    public void Apply_AdditiveBeforeMultiplicative()
+    {
+        var addMod = ModifierData.CreateForTest("add", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f);
+        var mulMod = ModifierData.CreateForTest("mul", ModifierScope.SelectedCategory,
+            ModifierEffectType.MultiplyFinalScore, 2f);
+
+        var modifiers = new List<ModifierData> { mulMod, addMod };
+        var result = ScoreResult.Create(20, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        // (20 + 10) * 2 = 60
+        Assert.AreEqual(60, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_CategoryLevelBeforeFinalScore()
+    {
+        var perDie = ModifierData.CreateForTest("perDie", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddPerDieValue, 5f, dieValue: 1);
+        var flat = ModifierData.CreateForTest("flat", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 100f);
+
+        var modifiers = new List<ModifierData> { flat, perDie };
+        var result = ScoreResult.Create(3, new[] { 1, 1, 1, 2, 3 }, YachtCategory.Ones);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        // FlatBonus = 15 (perDie: 5*3) + 100 (flat) = 115
+        // FinalScore = (3 + 115) * 1 = 118
+        Assert.AreEqual(118, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_ScopeFiltering_SkipsWrongScope()
+    {
+        var mod = ModifierData.CreateForTest("any", ModifierScope.AnyCategoryClosed,
+            ModifierEffectType.AddFlatToFinalScore, 50f);
+
+        var modifiers = new List<ModifierData> { mod };
+        var result = ScoreResult.Create(10, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        Assert.AreEqual(0, result.FlatBonus);
+        Assert.AreEqual(10, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_CategoryFilter_SkipsWrongCategory()
+    {
+        var mod = ModifierData.CreateForTest("fh", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 15f,
+            targetCategory: YachtCategory.FullHouse, hasCategoryFilter: true);
+
+        var modifiers = new List<ModifierData> { mod };
+        var result = ScoreResult.Create(5, new[] { 1, 1, 1, 1, 1 }, YachtCategory.Ones);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        Assert.AreEqual(0, result.FlatBonus);
+    }
+
+    [Test]
+    public void Apply_CategoryFilter_AppliesMatchingCategory()
+    {
+        var mod = ModifierData.CreateForTest("fh", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 15f,
+            targetCategory: YachtCategory.FullHouse, hasCategoryFilter: true);
+
+        var modifiers = new List<ModifierData> { mod };
+        var result = ScoreResult.Create(25, new[] { 3, 3, 3, 2, 2 }, YachtCategory.FullHouse);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        Assert.AreEqual(15, result.FlatBonus);
+        Assert.AreEqual(40, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_MultipleModifiers_CorrectOrder()
+    {
+        var perDieAdd = ModifierData.CreateForTest("pda", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddPerDieValue, 2f, dieValue: 3);
+        var perDieMul = ModifierData.CreateForTest("pdm", ModifierScope.SelectedCategory,
+            ModifierEffectType.MultiplyPerDieValue, 1.5f, dieValue: 3);
+        var flatAdd = ModifierData.CreateForTest("fa", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f);
+        var finalMul = ModifierData.CreateForTest("fm", ModifierScope.SelectedCategory,
+            ModifierEffectType.MultiplyFinalScore, 2f);
+
+        var modifiers = new List<ModifierData> { finalMul, flatAdd, perDieMul, perDieAdd };
+        // dice: [3, 3, 3, 1, 2] — 3 threes
+        var result = ScoreResult.Create(9, new[] { 3, 3, 3, 1, 2 }, YachtCategory.Threes);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        // Pass 1 (cat additive): perDieAdd: +2*3 = +6 FlatBonus
+        // Pass 2 (cat multiplicative): perDieMul: 1.5^3 = 3.375 Multiplier
+        // Pass 3 (final additive): flatAdd: +10 FlatBonus → total FlatBonus = 16
+        // Pass 4 (final multiplicative): finalMul: 3.375 * 2 = 6.75 Multiplier
+        // FinalScore = floor((9 + 16) * 6.75) = floor(168.75) = 168
+        Assert.AreEqual(6, result.FlatBonus + 10); // just check pipeline ran; full calc below
+        Assert.AreEqual(168, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_NullModifiers_DoesNotThrow()
+    {
+        var result = ScoreResult.Create(10, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        Assert.DoesNotThrow(() =>
+            ModifierPipeline.Apply(null, ref result, ModifierScope.SelectedCategory));
+
+        Assert.AreEqual(10, result.FinalScore);
+    }
+
+    [Test]
+    public void Apply_EmptyList_NoChange()
+    {
+        var modifiers = new List<ModifierData>();
+        var result = ScoreResult.Create(10, new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        ModifierPipeline.Apply(modifiers, ref result, ModifierScope.SelectedCategory);
+
+        Assert.AreEqual(10, result.FinalScore);
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/SaveSystemTests.cs b/Assets/Scripts/Tests/Editor/SaveSystemTests.cs
new file mode 100644
index 0000000..c5be098
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/SaveSystemTests.cs
@@ -0,0 +1,88 @@
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class SaveSystemTests
+{
+    [SetUp]
+    public void SetUp()
+    {
+        SaveSystem.Delete();
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SaveSystem.Delete();
+    }
+
+    [Test]
+    public void SaveAndLoad_RoundTrip_PreservesData()
+    {
+        var data = new SaveData
+        {
+            Currency = 999,
+            OwnedModifiers = new List<ModifierSaveEntry>
+            {
+                new() { ModifierId = "mod1", IsActive = true, RemainingUses = 3 },
+                new() { ModifierId = "mod2", IsActive = false, RemainingUses = -1 }
+            }
+        };
+
+        SaveSystem.Save(data);
+        var loaded = SaveSystem.Load();
+
+        Assert.AreEqual(999, loaded.Currency);
+        Assert.AreEqual(2, loaded.OwnedModifiers.Count);
+        Assert.AreEqual("mod1", loaded.OwnedModifiers[0].ModifierId);
+        Assert.IsTrue(loaded.OwnedModifiers[0].IsActive);
+        Assert.AreEqual(3, loaded.OwnedModifiers[0].RemainingUses);
+        Assert.AreEqual("mod2", loaded.OwnedModifiers[1].ModifierId);
+        Assert.IsFalse(loaded.OwnedModifiers[1].IsActive);
+    }
+
+    [Test]
+    public void Load_MissingKey_ReturnsDefault()
+    {
+        var loaded = SaveSystem.Load();
+
+        Assert.IsNotNull(loaded);
+        Assert.AreEqual(0, loaded.Currency);
+        Assert.AreEqual(0, loaded.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void HasSave_ReturnsFalseWhenEmpty()
+    {
+        Assert.IsFalse(SaveSystem.HasSave());
+    }
+
+    [Test]
+    public void HasSave_ReturnsTrueAfterSave()
+    {
+        SaveSystem.Save(new SaveData { Currency = 100 });
+
+        Assert.IsTrue(SaveSystem.HasSave());
+    }
+
+    [Test]
+    public void Delete_RemovesSaveData()
+    {
+        SaveSystem.Save(new SaveData { Currency = 100 });
+        SaveSystem.Delete();
+
+        Assert.IsFalse(SaveSystem.HasSave());
+    }
+
+    [Test]
+    public void Load_CorruptJson_ReturnsDefault()
+    {
+        PlayerPrefs.SetString("YachtDice_SaveData", "{invalid json!!!");
+        PlayerPrefs.Save();
+
+        var loaded = SaveSystem.Load();
+
+        Assert.IsNotNull(loaded);
+        Assert.AreEqual(0, loaded.Currency);
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/ScoringSystemTests.cs b/Assets/Scripts/Tests/Editor/ScoringSystemTests.cs
new file mode 100644
index 0000000..f85cd19
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/ScoringSystemTests.cs
@@ -0,0 +1,98 @@
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class ScoringSystemTests
+{
+    private ScoringSystem CreateScoringSystem()
+    {
+        var go = new GameObject("ScoringSystem");
+        return go.AddComponent<ScoringSystem>();
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        foreach (var go in Object.FindObjectsByType<ScoringSystem>(FindObjectsSortMode.None))
+            Object.DestroyImmediate(go.gameObject);
+    }
+
+    [Test]
+    public void PreviewScore_AppliesOnlySelectedCategoryModifiers()
+    {
+        var system = CreateScoringSystem();
+
+        var selectedMod = ModifierData.CreateForTest("sel", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f);
+        var anyCloseMod = ModifierData.CreateForTest("any", ModifierScope.AnyCategoryClosed,
+            ModifierEffectType.AddFlatToFinalScore, 100f);
+
+        system.SetActiveModifiers(new List<ModifierData> { selectedMod, anyCloseMod });
+
+        var result = system.PreviewScore(new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        // Only SelectedCategory mod should apply in preview
+        Assert.AreEqual(10, result.FlatBonus);
+        Assert.AreEqual(25, result.FinalScore); // (15 + 10) * 1
+    }
+
+    [Test]
+    public void ScoreCategory_AppliesBothScopes()
+    {
+        var system = CreateScoringSystem();
+
+        var selectedMod = ModifierData.CreateForTest("sel", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f);
+        var anyCloseMod = ModifierData.CreateForTest("any", ModifierScope.AnyCategoryClosed,
+            ModifierEffectType.AddFlatToFinalScore, 20f);
+
+        system.SetActiveModifiers(new List<ModifierData> { selectedMod, anyCloseMod });
+
+        var result = system.ScoreCategory(new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        // Both scopes should apply
+        Assert.AreEqual(30, result.FlatBonus);
+        Assert.AreEqual(45, result.FinalScore); // (15 + 30) * 1
+    }
+
+    [Test]
+    public void ScoreCategory_FiresOnCategoryConfirmed()
+    {
+        var system = CreateScoringSystem();
+        YachtCategory firedCategory = (YachtCategory)(-1);
+        ScoreResult firedResult = default;
+
+        system.OnCategoryConfirmed += (cat, res) =>
+        {
+            firedCategory = cat;
+            firedResult = res;
+        };
+
+        system.ScoreCategory(new[] { 1, 1, 1, 1, 1 }, YachtCategory.Ones);
+
+        Assert.AreEqual(YachtCategory.Ones, firedCategory);
+        Assert.AreEqual(5, firedResult.BaseScore);
+    }
+
+    [Test]
+    public void ScoreCategory_PreventsDuplicateCategory()
+    {
+        var system = CreateScoringSystem();
+        system.ScoreCategory(new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance);
+
+        Assert.Throws<System.InvalidOperationException>(() =>
+            system.ScoreCategory(new[] { 1, 2, 3, 4, 5 }, YachtCategory.Chance));
+    }
+
+    [Test]
+    public void ScoreCategory_WithNoModifiers_CalculatesBaseOnly()
+    {
+        var system = CreateScoringSystem();
+        var result = system.ScoreCategory(new[] { 6, 6, 6, 6, 6 }, YachtCategory.Yacht);
+
+        Assert.AreEqual(50, result.BaseScore);
+        Assert.AreEqual(0, result.FlatBonus);
+        Assert.AreEqual(1f, result.Multiplier);
+        Assert.AreEqual(50, result.FinalScore);
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/ShopModelTests.cs b/Assets/Scripts/Tests/Editor/ShopModelTests.cs
new file mode 100644
index 0000000..93c17ed
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/ShopModelTests.cs
@@ -0,0 +1,130 @@
+using NUnit.Framework;
+using UnityEngine;
+
+public sealed class ShopModelTests
+{
+    private CurrencyBank bank;
+    private InventoryModel inventory;
+    private ShopModel shop;
+
+    [SetUp]
+    public void SetUp()
+    {
+        var go = new GameObject("Bank");
+        bank = go.AddComponent<CurrencyBank>();
+        bank.SetBalance(500);
+
+        inventory = new InventoryModel(5);
+        shop = new ShopModel(bank, inventory);
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        foreach (var go in Object.FindObjectsByType<CurrencyBank>(FindObjectsSortMode.None))
+            Object.DestroyImmediate(go.gameObject);
+    }
+
+    [Test]
+    public void TryPurchase_SucceedsWithSufficientCurrency()
+    {
+        var mod = ModifierData.CreateForTest("test", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f, shopPrice: 100);
+
+        bool result = shop.TryPurchase(mod);
+
+        Assert.IsTrue(result);
+        Assert.AreEqual(400, bank.Balance);
+        Assert.AreEqual(1, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void TryPurchase_FailsWhenBroke()
+    {
+        bank.SetBalance(10);
+        var mod = ModifierData.CreateForTest("test", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f, shopPrice: 100);
+
+        bool result = shop.TryPurchase(mod);
+
+        Assert.IsFalse(result);
+        Assert.AreEqual(10, bank.Balance);
+        Assert.AreEqual(0, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void TryPurchase_PermanentCannotBeBoughtTwice()
+    {
+        var mod = ModifierData.CreateForTest("perm", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f,
+            durability: ModifierDurability.Permanent, shopPrice: 100);
+
+        shop.TryPurchase(mod);
+        bool secondResult = shop.TryPurchase(mod);
+
+        Assert.IsFalse(secondResult);
+        Assert.AreEqual(400, bank.Balance);
+        Assert.AreEqual(1, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void TryPurchase_LimitedCanBeReBought()
+    {
+        var mod = ModifierData.CreateForTest("limited", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f,
+            durability: ModifierDurability.LimitedUses, maxUses: 3, shopPrice: 100);
+
+        shop.TryPurchase(mod);
+        bool secondResult = shop.TryPurchase(mod);
+
+        Assert.IsTrue(secondResult);
+        Assert.AreEqual(300, bank.Balance);
+        Assert.AreEqual(2, inventory.OwnedModifiers.Count);
+    }
+
+    [Test]
+    public void TryPurchase_FiresPurchaseEvent()
+    {
+        ModifierData purchased = null;
+        shop.OnItemPurchased += data => purchased = data;
+
+        var mod = ModifierData.CreateForTest("test", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f, shopPrice: 100);
+
+        shop.TryPurchase(mod);
+
+        Assert.IsNotNull(purchased);
+        Assert.AreEqual("test", purchased.Id);
+    }
+
+    [Test]
+    public void GetItemState_Available_WhenCanAfford()
+    {
+        var mod = ModifierData.CreateForTest("test", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f, shopPrice: 100);
+
+        Assert.AreEqual(ShopItemState.Available, shop.GetItemState(mod));
+    }
+
+    [Test]
+    public void GetItemState_TooExpensive_WhenCannotAfford()
+    {
+        bank.SetBalance(10);
+        var mod = ModifierData.CreateForTest("test", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f, shopPrice: 100);
+
+        Assert.AreEqual(ShopItemState.TooExpensive, shop.GetItemState(mod));
+    }
+
+    [Test]
+    public void GetItemState_Owned_WhenPermanentPurchased()
+    {
+        var mod = ModifierData.CreateForTest("perm", ModifierScope.SelectedCategory,
+            ModifierEffectType.AddFlatToFinalScore, 10f,
+            durability: ModifierDurability.Permanent, shopPrice: 100);
+
+        shop.TryPurchase(mod);
+
+        Assert.AreEqual(ShopItemState.Owned, shop.GetItemState(mod));
+    }
+}
diff --git a/Assets/Scripts/Tests/Editor/YachtDice.Tests.Editor.asmdef b/Assets/Scripts/Tests/Editor/YachtDice.Tests.Editor.asmdef
new file mode 100644
index 0000000..745698e
--- /dev/null
+++ b/Assets/Scripts/Tests/Editor/YachtDice.Tests.Editor.asmdef
@@ -0,0 +1,24 @@
+{
+    "name": "YachtDice.Tests.Editor",
+    "rootNamespace": "",
+    "references": [
+        "UnityEngine.TestRunner",
+        "UnityEditor.TestRunner",
+        "YachtDice.Runtime"
+    ],
+    "includePlatforms": [
+        "Editor"
+    ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": true,
+    "precompiledReferences": [
+        "nunit.framework.dll"
+    ],
+    "autoReferenced": false,
+    "defineConstraints": [
+        "UNITY_INCLUDE_TESTS"
+    ],
+    "versionDefines": [],
+    "noEngineReferences": false
+}
diff --git a/Assets/Scripts/UI/GameController.cs b/Assets/Scripts/UI/GameController.cs
index a431dd2..385632b 100644
--- a/Assets/Scripts/UI/GameController.cs
+++ b/Assets/Scripts/UI/GameController.cs
@@ -14,8 +14,14 @@ public sealed class GameController : MonoBehaviour
     [SerializeField] private DicePanelView dicePanelView;
     [SerializeField] private GameInfoView gameInfoView;
 
+    [Header("Economy & Modifiers")]
+    [SerializeField] private CurrencyBank currencyBank;
+    [SerializeField] private ShopController shopController;
+    [SerializeField] private InventoryController inventoryController;
+
     [Header("Settings")]
     [SerializeField] private int maxRollsPerTurn = 3;
+    [SerializeField] private int maxActiveModifierSlots = 5;
 
     private static readonly YachtCategory[] UpperCategories =
     {
@@ -28,6 +34,9 @@ public sealed class GameController : MonoBehaviour
 
     private int totalCategoryCount;
 
+    private InventoryModel inventoryModel;
+    private ShopModel shopModel;
+
     // ── Lifecycle ──────────────────────────────────────────────
 
     private void Awake()
@@ -46,6 +55,14 @@ public sealed class GameController : MonoBehaviour
         dicePanelView.OnRollClicked += HandleRollClicked;
         dicePanelView.OnDiceToggled += HandleDiceToggled;
         gameInfoView.OnNewGameClicked += HandleNewGameClicked;
+        gameInfoView.OnShopClicked += HandleShopClicked;
+        gameInfoView.OnInventoryClicked += HandleInventoryClicked;
+
+        // Currency
+        if (currencyBank != null)
+            currencyBank.OnBalanceChanged += HandleCurrencyChanged;
+
+        InitializeModifierSystems();
     }
 
     private void OnDestroy()
@@ -60,6 +77,100 @@ public sealed class GameController : MonoBehaviour
         dicePanelView.OnRollClicked -= HandleRollClicked;
         dicePanelView.OnDiceToggled -= HandleDiceToggled;
         gameInfoView.OnNewGameClicked -= HandleNewGameClicked;
+        gameInfoView.OnShopClicked -= HandleShopClicked;
+        gameInfoView.OnInventoryClicked -= HandleInventoryClicked;
+
+        if (currencyBank != null)
+            currencyBank.OnBalanceChanged -= HandleCurrencyChanged;
+
+        if (inventoryModel != null)
+            inventoryModel.OnInventoryChanged -= HandleInventoryChangedForSave;
+    }
+
+    // ── Modifier System Init ─────────────────────────────────
+
+    private void InitializeModifierSystems()
+    {
+        inventoryModel = new InventoryModel(maxActiveModifierSlots);
+        inventoryModel.OnInventoryChanged += HandleInventoryChangedForSave;
+
+        ShopCatalog catalog = shopController != null ? shopController.Catalog : null;
+
+        shopModel = new ShopModel(currencyBank, inventoryModel);
+
+        LoadSaveData(catalog);
+
+        if (inventoryController != null)
+            inventoryController.Initialize(inventoryModel);
+
+        if (shopController != null)
+            shopController.Initialize(shopModel);
+
+        if (currencyBank != null)
+            gameInfoView.SetCurrencyText(currencyBank.Balance);
+    }
+
+    private void LoadSaveData(ShopCatalog catalog)
+    {
+        SaveData save = SaveSystem.Load();
+
+        if (currencyBank != null && save.Currency > 0)
+            currencyBank.SetBalance(save.Currency);
+
+        if (catalog != null && save.OwnedModifiers.Count > 0)
+        {
+            var runtimeList = new List<ModifierRuntime>();
+            var permanentIds = new HashSet<string>();
+
+            for (int i = 0; i < save.OwnedModifiers.Count; i++)
+            {
+                var entry = save.OwnedModifiers[i];
+                ModifierData data = catalog.FindById(entry.ModifierId);
+
+                if (data == null)
+                {
+                    Debug.LogWarning($"Modifier '{entry.ModifierId}' not found in catalog, skipping.");
+                    continue;
+                }
+
+                var runtime = new ModifierRuntime
+                {
+                    ModifierId = entry.ModifierId,
+                    IsActive = entry.IsActive,
+                    RemainingUses = entry.RemainingUses,
+                    Data = data
+                };
+
+                runtimeList.Add(runtime);
+
+                if (data.Durability == ModifierDurability.Permanent)
+                    permanentIds.Add(data.Id);
+            }
+
+            inventoryModel.LoadState(runtimeList);
+            shopModel.LoadPurchasedPermanentIds(permanentIds);
+        }
+    }
+
+    private void PerformSave()
+    {
+        var save = new SaveData
+        {
+            Currency = currencyBank != null ? currencyBank.Balance : 0
+        };
+
+        var owned = inventoryModel.GetAllForSave();
+        for (int i = 0; i < owned.Count; i++)
+        {
+            save.OwnedModifiers.Add(new ModifierSaveEntry
+            {
+                ModifierId = owned[i].ModifierId,
+                IsActive = owned[i].IsActive,
+                RemainingUses = owned[i].RemainingUses
+            });
+        }
+
+        SaveSystem.Save(save);
     }
 
     // ── Model Event Handlers ──────────────────────────────────
@@ -93,6 +204,7 @@ public sealed class GameController : MonoBehaviour
     {
         scoreCardView.SetCategoryScored(category, finalScore);
         UpdateTotalDisplay();
+        PerformSave();
     }
 
     private void HandleGameOver(int totalScore)
@@ -103,6 +215,7 @@ public sealed class GameController : MonoBehaviour
 
         int displayTotal = CalculateDisplayTotal();
         gameInfoView.ShowGameOver(displayTotal);
+        PerformSave();
     }
 
     // ── View Event Handlers ───────────────────────────────────
@@ -145,6 +258,43 @@ public sealed class GameController : MonoBehaviour
         gameManager.StartNewGame();
     }
 
+    private void HandleShopClicked()
+    {
+        if (shopController != null)
+        {
+            var shopView = shopController.GetComponentInChildren<ShopView>(true);
+            if (shopView != null)
+            {
+                if (shopView.IsVisible) shopView.Hide();
+                else shopView.Show();
+            }
+        }
+    }
+
+    private void HandleInventoryClicked()
+    {
+        if (inventoryController != null)
+        {
+            var inventoryView = inventoryController.GetComponentInChildren<InventoryView>(true);
+            if (inventoryView != null)
+            {
+                if (inventoryView.IsVisible) inventoryView.Hide();
+                else inventoryView.Show();
+            }
+        }
+    }
+
+    private void HandleCurrencyChanged(int newBalance)
+    {
+        gameInfoView.SetCurrencyText(newBalance);
+        PerformSave();
+    }
+
+    private void HandleInventoryChangedForSave()
+    {
+        PerformSave();
+    }
+
     // ── Helpers ────────────────────────────────────────────────
 
     private void UpdatePreviewScores(int[] diceValues)
diff --git a/Assets/Scripts/UI/GameInfoView.cs b/Assets/Scripts/UI/GameInfoView.cs
index e8b4e84..575efd0 100644
--- a/Assets/Scripts/UI/GameInfoView.cs
+++ b/Assets/Scripts/UI/GameInfoView.cs
@@ -8,17 +8,31 @@ public sealed class GameInfoView : MonoBehaviour
     [Header("Turn Info")]
     [SerializeField] private TMP_Text turnText;
 
+    [Header("Currency")]
+    [SerializeField] private TMP_Text currencyText;
+
+    [Header("Navigation")]
+    [SerializeField] private Button shopButton;
+    [SerializeField] private Button inventoryButton;
+
     [Header("Game Over Overlay")]
     [SerializeField] private GameObject gameOverPanel;
     [SerializeField] private TMP_Text finalScoreText;
     [SerializeField] private Button newGameButton;
 
     public event Action OnNewGameClicked;
+    public event Action OnShopClicked;
+    public event Action OnInventoryClicked;
 
     private void Awake()
     {
         newGameButton.onClick.AddListener(() => OnNewGameClicked?.Invoke());
         gameOverPanel.SetActive(false);
+
+        if (shopButton != null)
+            shopButton.onClick.AddListener(() => OnShopClicked?.Invoke());
+        if (inventoryButton != null)
+            inventoryButton.onClick.AddListener(() => OnInventoryClicked?.Invoke());
     }
 
     public void SetTurnText(int turn, int maxTurns)
@@ -26,6 +40,12 @@ public sealed class GameInfoView : MonoBehaviour
         turnText.text = $"Ход {turn} / {maxTurns}";
     }
 
+    public void SetCurrencyText(int amount)
+    {
+        if (currencyText != null)
+            currencyText.text = amount.ToString();
+    }
+
     public void ShowGameOver(int finalScore)
     {
         gameOverPanel.SetActive(true);
@@ -40,5 +60,10 @@ public sealed class GameInfoView : MonoBehaviour
     private void OnDestroy()
     {
         newGameButton.onClick.RemoveAllListeners();
+
+        if (shopButton != null)
+            shopButton.onClick.RemoveAllListeners();
+        if (inventoryButton != null)
+            inventoryButton.onClick.RemoveAllListeners();
     }
 }
diff --git a/Assets/Scripts/YachtDice.Runtime.asmdef b/Assets/Scripts/YachtDice.Runtime.asmdef
new file mode 100644
index 0000000..d26c022
--- /dev/null
+++ b/Assets/Scripts/YachtDice.Runtime.asmdef
@@ -0,0 +1,18 @@
+{
+    "name": "YachtDice.Runtime",
+    "rootNamespace": "",
+    "references": [
+        "Unity.TextMeshPro",
+        "Unity.InputSystem",
+        "Newtonsoft.Json"
+    ],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": false,
+    "precompiledReferences": [],
+    "autoReferenced": true,
+    "defineConstraints": [],
+    "versionDefines": [],
+    "noEngineReferences": false
+}