How to reference separate value of a cloned list

Unity Engine
1

I have make a shop system which can fill a list of scriptable object(ShopItem) to a shop slot prefab, which than clone itself with the data of different shop items.
But when it comes to the buy button, I don’t know how to reference the separate value of a item from the shop list. The buy button now reduce the combine value of all items on the list.

public class BuyButton : MonoBehaviour
{
    public int itemID;
    public void BuyItem()
    {
        for (int i = 0; i < Shop.shop.shopItemList.Count; i++)
        {
            if (GameManager.gameManager.CheckMoney(Shop.shop.shopItemList[i].value))
            {
                GameManager.gameManager.ReduceMoney(Shop.shop.shopItemList[i].value);
            }
        }
    }
}

    public void ReduceMoney(float amount)
    {
        money -= amount;
        UpdateUI();
    }

    public bool CheckMoney(float amount)
    {
        if (amount <= money)
        {
            return true;
        }
        return false;
    }
2

Nevermind, I figured it out myself.
Just add itemID to the script and everything work.

if (Shop.shop.shopItemList[i].itemID == itemID)