Deutsch Perfekt is running a special, Buy 4 for the Price of 3!

Click here to read the specials (it's in German). Under "Zahlungsweise," be sure to select the correct option, whether by credit card (Kreditkarte), direct withdrawal (Lastschrift), or on invoice (Rechnung). Unless you have a bank account in Germany, or don't mind paying international wire transfer fees, it's possibly the cheaper option to pay by credit card.