How can I pay for the book? You can pay for the book using your credit or debit card. We accept VISA, Mastercard, and Amex. Payment is deducted in Euros according to the current exchange rate. Your payment is secured via the GoPay payment gateway. You can also pay using the PayPal service, either in the typical way, or you can use it as a payment gateway for your VISA, Mastercard, or Amex card.