not really sure but whatever

Assets/Scripts/EntityPlayer.cs

@@ -9,11 +9,14 @@ public enum ControlMode {
 
 public class EntityPlayer : Entity
 {
+    public Inventory inventory;
+
     protected ControlMode controlMode;
     protected Animator animator;
 
     protected override void Start() {
         base.Start();
+        inventory = new Inventory();
         animator = GetComponent<Animator>();
         controlMode = ControlMode.Move;
     }

Assets/Scripts/Inventory.cs

@@ -0,0 +1,47 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+[System.Serializable]
+public class ItemNotInInventoryException : System.Exception
+{
+    public ItemNotInInventoryException() { }
+    public ItemNotInInventoryException(string message) : base(message) { }
+    public ItemNotInInventoryException(string message, System.Exception inner) : base(message, inner) { }
+    protected ItemNotInInventoryException(
+        System.Runtime.Serialization.SerializationInfo info,
+        System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+}
+
+public class Inventory {
+    public List<InventoryItem> items;
+
+    public InventoryItem GetItemByName(string name) {
+        foreach(InventoryItem item in items) {
+            if(name == item.Name) 
+            {
+                return item;
+            }
+        }
+        return null;
+    }
+
+    public void AddItem(InventoryItem item) {
+        //Check if it's mergeable 
+        InventoryItem other = GetItemByName(item.Name);
+        if(other == null) {
+            items.Add(item);
+        }
+        else {
+            other.quantity += item.quantity;
+        }
+    }
+
+    public void UseItem(InventoryItem item) {
+        if(!items.Contains(item)) throw new ItemNotInInventoryException();
+        item.Use();
+        if(item.quantity <= 0) {
+            items.Remove(item);
+        }
+    }
+}

Assets/Scripts/Inventory.cs.meta

@@ -0,0 +1,11 @@
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+guid: 52aeb2895cff09140a9bc5981d3efc8e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/InventoryItem.cs

@@ -0,0 +1,25 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class InventoryItem {
+
+    public int quantity = 1;
+
+    public virtual string Name {
+        //Two items with the same name will stack!
+        get {
+            Debug.LogError("No name given to an item");
+            return "";
+        }
+    } 
+
+    public virtual void Use() {
+        Debug.LogWarning("Use not overridden");
+        quantity -= 1;
+    }
+
+    public InventoryItem(int quantity) {
+        this.quantity = quantity;
+    }
+}

Assets/Scripts/InventoryItem.cs.meta

@@ -0,0 +1,11 @@
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+guid: af1bf08d5ae9ead4796f0b9ade785254
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
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