Great resource for getting the best price on textbookswww.bigwords.com.
You can search for all your textbooks for all your classes at the same time. They compare many different online stores including amazon, ebay, half.com, abesbooks, etc, then they tell you who would be the cheapest if you want to buy all your books from the same store, and also the lowest price at all the different stores on each book. They also show you all the shipping deals and coupons available at the different stores. Bigwords is a great website and saves time and money. Ya gotta love it!