World's largest second-hand book shop

Like most bloggers, I enjoy reading. It's hard to source books in India, and new books can be expensive. However, the second hand books on www.amazon.com are brilliant value for money ! I buy them online, ship them to a dear friend in the USA, who then M-Bags them to me - and an M-Bag costs only about US $ 1.00 for a pound of books, which makes the shipping affordable too ! This is how I buy most of the books for HELP, the world's largest health library for people.