BookMoochShare, exchange books.
Every time you give someone a book, you earn points and can get any book you want in BookMooch. After you have read the book, you can leave it to yourself or return it back to BookMooch for others.
In order to receive regularly, you need to give 2 books for one.The site renders charitable help to organizations and you can Give your points to charity: children's hospitals (a sick child can get a free book), a library fund, an African literacy program. You can request books from other countries, and in other languages. You get 3 points when sending a book from your country, as compensation for a more expensive shipment.
Exchange books or buy at a good price.