Ok, so I randomly came upon this site while messing around on the internet. Chegg.com allows you to rent your textbooks and thus save a ton of money off the list price for those books. I'm not a 100% believer in this but I could see how this would prove to be helpful for some. You rent your textbooks from them and then when you are done you send them back (via UPS and they pay for it). End of story.
I guess if you didn't want the hassle of trying to then resell your textbooks when you were finished with them, this could be an avenue for you. The website claims that renting can be much cheaper than buying used textbooks. You are helping the environment when you rent from them since they plant a tree every time you rent. They also allow you to sell your textbooks to them. This could be valuable if you want to see how much you can get for your textbooks from an outside source that isn't your school bookstore. Check and note how much Chegg would give you and then go try to sell your books back to the bookstore and decide from there which gives you more money back. Gotta save where you can in college right?