BookFinder

Book Finder is a neat site/tool that allows you to compare prices on more than 125 million books for sale from 4,000 sellers. So there’s no need to go to Amazon, Half.com and all the other book sites when Book Finder can search them for you.

When searching for titles, make sure you select the appropriate edition! A test search for a Women's Studies text found entries for all three recent editions, though mostly for the first two.