Best place (online) to buy used textbooks?

I would recommend using a price comparison site like AddAll, which searches for the best price of a book across dozens of online stores. I have found that there isn't one single online store that consistently has the lowest price (it depends on the particular book). However, keep in mind that you may ultimately want to place your order from a single online store to save on shipping costs.

Try ABEbook.com. There are several vender's that specialize in text books and the competition to under sell each other always works to your benefit.

eBay.com is the way to go. my sister buys all her college books form ebay and get them for really cheap. for example she had to buy a marketting essentials book that has a retail price of about $375 - she got it at ebay for $40 which is a good bargain.All bidding on a book can lower the cost

i really like campusbooks.com - that may just be because i like price comparison websites a lot better.. but they do a pretty good job, and their website is kinda fun. ;-)

TextBookFlix is an interesting, new way to get textbooks. As the name suggests, it's Netflix for textbooks. However, unlike Netflix, there is no monthly subscription fee. You just pay a one-time fee for each book you use each semester.

The service is currently in an invite-only beta. To get access, you need to sign up for the waiting list. In the meantime, you can search through the catalog and calculate prices.

All those sites still never compare to the selection and (usually) great price of Amazon.com