I complain a lot about how I'm still trying to sell back my textbooks from college and those books that I paid $100 for -- I'm only getting $4 back. I learned a little too late in the game about renting textbooks and when I did, it changed my life. I was paying way less for a book and I didn't have to worry about selling it back - which can be a huge hassel.
Campus Book Rentals is a great site for finding textbooks to rent for the semester. You don't have to pay for shipping either way and you can still highlight the textbook - just like it's your own. But, you're saving 40%-90%!
And for everyone else that still has a ton of textbooks you can't get rid of, Campus Book Rentals has a great program where you can rent out your own textbook called RentBack. Do that for a few semesters and you'll be able to make 2 to 4 times more than if you just sold it back.
Want to learn more about it? Check out this video:
College books are expensive and I cannot recommend enough that you rent those books to keep your costs down.