public void Buy(Player_Model player, Item_Model item, int Amount)
        {
            int priceToPay = item.Price * Amount;
            var seller     = Players.Find(x => x.ID == item.PlayerID);

            if (seller == null)
            {
                throw new Exception();
            }

            if (Amount > item.Quantity)
            {
                throw new IndexOutOfRangeException();
            }
            else if (Amount == item.Quantity)
            {
                player.AddCash(-priceToPay);
                seller.AddCash(priceToPay);
                Items.Remove(item);
            }
            else
            {
                player.AddCash(-priceToPay);
                seller.AddCash(priceToPay);

                Items.Remove(item);
                item.Quantity -= Amount;
                Items.Add(item);
            }
        }
 public void MakeOffer(Item_Model item, bool isComercial = false)
 {
     if (isComercial)
     {
         Items.Insert(0, item);
     }
     else
     {
         Items.Add(item);
     }
 }