As any college student knows, textbook has an inflated price if you buy from campus book store. For the same book, one can find a copy with a fraction of the price charged by campus store from the Web. Amazon third party sellers, eBay's half.com, all provide convenient search. But dedicated shopbot for books give one an edge in terms of aggregating all these prices from amazon, half.com and other online book stores. Specialized college textbook shopbots include campusbooks.com. Bookfinder.com provides a nice special page for searching textbook.

There are also shopbot for general book price comparison like addall.com.

College related websites like cheapscholar.org used comparison engine powered by campusbooks.com to help visitor find good price for textbooks: http://cheapscholar.org/2010/05/14/textbook-comparison-shopping-tool/