Rent your textbooks instead of buying them at BookRenter.com. As long as you are able to keep your textbooks in reasonably good condition, you will only have to pay 20-30% of the book's actual cost. This is a good option instead of buying the book and then selling it back to the college bookstore at a fraction of the original cost.
Read an article about BookRenter at Central Florida Future.
(See the post on Library Stuff where I found out about BookRenter.com)