private void OpSellItem(int itemId)
        {
            Console.WriteLine("How many would you like to sell?");
            int quantity = SetQuantity();

            switch (itemId)
            {
            // case to sell pizza
            case 3:
                if (MyShip.GetItemQuant(itemId) >= quantity)
                {
                    // enforces unique economy
                    MyShip.ChangeCredits(MyShip.GetPrice(0) * quantity);
                    // adds to lifetime earnings to be displayed at end of game
                    MyShip.ChangeTotalEarned(MyShip.GetPrice(0) * quantity);
                    // removes sold item(s) from cargo inventory
                    MyShip.ChangeItem(3, -quantity);
                    // removes weight from cargo
                    MyShip.ChangeWeight(150 * -quantity);

                    Console.Clear();
                    Console.WriteLine($"Item sold. Credits = {MyShip.GetCredits()}");
                }
                else
                {
                    SellError();
                }
                break;

            // case to sell Op1Item item. See above for general case statement notes.
            case 4:
                if (MyShip.GetItemQuant(itemId) >= quantity)
                {
                    MyShip.ChangeCredits(MyShip.GetPrice(-1) * quantity);
                    MyShip.ChangeTotalEarned(MyShip.GetPrice(-1) * quantity);
                    MyShip.ChangeItem(4, -quantity);
                    MyShip.ChangeWeight(150 * -quantity);
                    Console.Clear();
                    Console.WriteLine($"Item sold. Credits = {MyShip.GetCredits()}");
                }
                else
                {
                    SellError();
                }
                break;

            case 5:
                if (MyShip.GetItemQuant(itemId) >= quantity)
                {
                    MyShip.ChangeCredits(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeTotalEarned(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeItem(5, -quantity);
                    MyShip.ChangeWeight(150 * -quantity);
                    Console.Clear();
                    Console.WriteLine($"Item sold. Credits = {MyShip.GetCredits()}");
                }
                else
                {
                    SellError();
                }
                break;

            case 6:
                if (MyShip.GetItemQuant(itemId) >= quantity)
                {
                    MyShip.ChangeCredits(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeTotalEarned(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeItem(6, -quantity);
                    MyShip.ChangeWeight(150 * -quantity);
                    Console.Clear();
                    Console.WriteLine($"Item sold. Credits = {MyShip.GetCredits()}");
                }
                else
                {
                    SellError();
                }
                break;

            case 7:
                if (MyShip.GetItemQuant(itemId) >= quantity)
                {
                    MyShip.ChangeCredits(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeTotalEarned(MyShip.GetPrice(1) * quantity);
                    MyShip.ChangeItem(7, -quantity);
                    MyShip.ChangeWeight(150 * -quantity);
                    Console.Clear();
                    Console.WriteLine($"Item sold. Credits = {MyShip.GetCredits()}");
                }
                else
                {
                    SellError();
                }
                break;

            default:
                TradeError();
                break;
            }
        }