There are a number of people (eg "Leaping Gnome") on this forum who have, in the past, kindly offered to buy Connect gift certificates on behalf of non-US members of this forum, which can then be used on the Connect store without needing a US-registered credit card. You pay him by PayPal, and he then buys the certificate for you and sends you the number to enter in the Connect store.
There are, however, many sources of books other than the "Connect" store. There are 10s of thousands of out-of-copyright books available from such sites as
http://www.manybooks.net or Project Gutenberg. If you like SciFi/Fantasy, there's Baen, who publish books at sensible prices in open formats. There are other sources too.