Online Shops For Used and Rare Books

The Saadhu's Choice.

These bookstores specialize in used and out of print books. That rare book you have been hunting all over the city may be available with one of them.

paperbacktradeinn.com: The place to buy used books. And once you have finished reading it, sell it again. They specialise in Fiction.
textbooks.com: Though new text books are very expensive, used textbooks from textbooks.com are much lower in price. They will buy back your books too once you are through with them.
digibib.com: Digital Bibliophile Community. They provide an interesting and useful online environment for buying, selling, and learning about used and rare books.
The Old Bookroom: The Old Bookroom carries a wide range of in print and out of print books on Asia. Visit their site at http://www.OldBookroom.com
Bibliocity
Bookavenue
Antiqbook