problem with PurchaseItemRequest

I would like to pass 2 parameters to the PurchaseItemRequest, i.e. the name and price. If I now click on the button an error occurs. Can someone help me what i'm doing wrong i am a beginner

public class BuySkins : MonoBehaviour
{

    public Button spacie;
    public Button Ninjo;
    public Item i;

    public void Start()
    {

        i = GameObject.FindObjectOfType<Item>();

        Ninjo.GetComponent<Button>().onClick.AddListener(delegate { MakePurchase(i.Name, i.Coast); });
        spacie.GetComponent<Button>().onClick.AddListener(delegate { MakePurchase(i.Name, i.Coast); });


    }
   

    public void MakePurchase(string name, int price)
    {
        PlayFabClientAPI.PurchaseItem(new PurchaseItemRequest
        {
            // In your game, this should just be a constant matching your primary catalog
            CatalogVersion = "Heros",
            VirtualCurrency = "DC",
            ItemId = name,
            Price = price,

        }, LogSuccess, LogFailure) ;
    }

    private void LogFailure(PlayFabError obj)
    {
        print("fehler aufgetretten beim kaufen");
    }

    private void LogSuccess(PurchaseItemResult obj)
    {
        print("gekauft");
    }
}