One thing that readers need to be aware of is that sites like Chegg are not very forgiving if a user/borrower has a penchant for highlighting or writing in the books. If you like to highlight, do so sparingly, because you will take a hit from the renter if there's too much in the book.
Your best bet is to buy used from a site like amazon, barnes&noble, ebay or craigslist. Often the cost is nominally more than that of a rental, and you should still be able to sell the book back at the end of the term (unless a new edition comes out).
