When I ran across the book Attic about a year ago, I was in hog heaven! I had previously be traveling to a chain store that was much farther away - this not only saved time, but gas! The Book Attic specializes in used books - they are half off of the publishers price - althought the shop is a bit small, there's always something to find. They also encourage customers to bring books back in for trade - They will issue you a store credit for your traded books.
PROS: local, book trade-ins
CONS: no monetary value for book trades, don't always have the latests books