New - Brand new textbooks.

Used - Like a traditional used bookstore. All the books are sold out of the same storefront, so you pay just one shipping fee for your entire purchase.

Marketplace - In a marketplace, individual sellers (students, small booksellers, etc.) list their new and used textbooks for sale. Prices are almost always better here than in a used bookstore, but you'll have to pay a separate shipping fee for each book sold by a different seller.

price comparison tools

Type in the book you want, and these sites will tell you what it costs (new & used) at dozens of stores across the web. Shipping costs, available coupons and any taxes are also listed.

BigWords.com
CampusI
Cheapest Textbooks