private void Purchase(String s)
        {
            if (Int32.TryParse(s, out int id))
            {
                Console.Write(@"
Enter quantity to purchase: ");
                s = Console.ReadLine();
                if (Int32.TryParse(s, out int quantity))
                {
                    try
                    {
                        // this will just throw an error if the productID doesn't exist, to give a more accurate error message
                        var product = c.GetProductNameByID(id);

                        c.BuyProduct(currentStoreID, id, quantity);

                        Console.WriteLine($"You bought {quantity} of {product}!");
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine(e.Message);
                    }
                }
                else if (s == "" || s == "\n")
                {
                    return;
                }
            }
            else if (s == "" || s == "\n")
            {
                return;
            }
        }