public double AddItem(Merchandise newItem) { if (Items.Any(item => item.Equals(newItem))) { Quantity[newItem.Type + ":" + newItem.Name]++; } else { Items.Add(newItem); Quantity[newItem.Type + ":" + newItem.Name] = 1; } Total = 0; foreach (Merchandise i in Items) { int quantity = Quantity[i.Type + ":" + i.Name]; Total += i.Price * quantity; } List <double> discounts = BulkBuy(); Total = Total - discounts[0] - discounts[1]; return(Total); }