Made price of upgrade be required

Assets/Scripts/UI/BuildingUnlockButton.cs

@@ -1,5 +1,6 @@
 using System.Text.RegularExpressions;
 using Fruitomation.Game;
+using Fruitomation.Global;
 using UnityEngine.UI;
 using UnityEngine;
 
@@ -28,16 +29,26 @@ namespace Fruitomation.UI
             string formatted = Regex.Replace(Building.ToString(), "[A-Z]", " $0")[1..];
             bool unlocked = UpgradeManager.Is(Building);
             
+            string cost = Cost == 0f ? "UNAVAILABLE" : $"{Cost:F1}";
             AttachedText.text = unlocked
                 ? $"{formatted}\nUnlocked"
-                : $"{formatted}\n{Cost:F1}";
+                : $"{formatted}\n{cost}";
             
             AttachedButton.interactable = !unlocked;
         }
 
         private void OnButtonClicked()
         {
-            UpgradeManager.Unlock(Building);
+            if (Cost == 0f)
+            {
+                Debug.LogWarning("Upgrade Cost has not been set");
+                return;
+            }
+
+            if (MoneyController.CanBuy(Cost))
+            {
+                UpgradeManager.Unlock(Building);
+            }
         }
     }
 }