One of my classmates directed me to
BIGWORDS.com | Buy Textbooks | Sell Textbooks | Used College Textbooks | New College Textbooks | Textbook Price Comparison | Cheap Textbooks | Cheapest Textbooks | Compare Textbook Prices | Textbook Buyback | Textbook Price Bot | New and Used Music | last semester and it has been a life saver!

They don't sell textbooks directly on that site but you enter in your isbn numbers or book title and then it will search all of the top websites like half.com, amazon, etc for you and then show you how much the book is on each site. I have started buying most of mine from
Chegg.com - Cheap Textbook Rentals. Search for Used Textbooks and Rent College Textbooks., it's a textbook rental site. You pay a much lower price for the book and then when the semester is over, you mail the book back to them. I used bigwords.com to buy 5 books yesterday and saved almost $300!