static void Main(string[] args)
        {
            VendingMachine vm   = new VendingMachine();
            User           user = new User();

            Console.WriteLine("Add some money:");
            vm.PrintMoney();
            user.IncreaseBalance(); //Clears console
            user.PurchaseProduct();
            vm.ReturnChange(user.Balance);

            /*TODO
             * Add another product type
             * Show message about how the product is used, being different for all product types.
             * Items should inherit methods to be overriden from an interface. (I have no methods to inherit :<)
             * Examine item option to show everything about it.
             */
        }