Incoming freshman, just a heads up:
Prepare for ridiculously high prices, long lines and extremely low book buybacks!
But, if you plan early enough, you can buy your books online! (However, make sure that you have purchased the right edition)
Some good sites to use are:
If you do buy your books from the FSU Bookstore or Bills and at the end of the semester and you are trying to do book buyback and they don't want to buy back your book, try it again next semester and there is a good chance they'll buy it because they may be using that book again.