I thought I would pass on a few tips that Ireceived about Internet book buying.
These are good first choices (though I often try www.half.com early on as well). They look in multiple locations, as well as new and used prices from Amazon, Barnes & Noble, Books-A-Million, Powells, and others.
These are book liquidators. Many of the books are remainders. The books may have marks or wear on these, but the marks don't effect the readability of the books. These sites (I especially like the third site) offer great prices, and Edward Hamilton offers a flat rate shipping that is unbeatable.
These are specialty book sites.
Useful for used, out of print, antiquarian and collectible books.