He could get a pre-paid credit card. Amazon will take them with the following restrictions:
If you are using a Visa, MasterCard, or American Express pre-paid credit or gift card, please note the following restrictions:
* Pre-paid gift cards can't be combined with credit cards on a single order.
* Pre-paid gift cards can't be used to sign up for Amazon Prime membership.
* Amex Gift Cards can't be used to purchase Amazon.com gift cards.
* Some banks may require you to register pre-paid gift cards with your name and billing address by calling the number on the back of the card.
* Amazon.com does not support entering the three-digit CVV code normally found on the back of some cards. If entering the code is required by the issuing bank, your payment may not process successfully.
* We will process a $1 authorization at the time of order to make sure the payment method is valid. This authorization is not a charge, but your bank may hold the authorized funds as unavailable until the authorization expires.
Or you could load up the Kindle with the free books from MR.