Renting Textbooks

I keep reading about how renting textbooks is such a "good deal."  In my honest opinion, I think that renting is almost as big a rip off as is buying textbooks new (or even used, in most cases) from your college bookstore.  Buying used (or sometimes new is even cheaper) on abebooks.com, half.com, amazon.com, betterworldbooks.com, or alibris.com is easier (you aren't limited to the amount of time you keep the books), cheaper, and you can write and highlight in the books as much as you want.  And then you can sell them back at most of the same websites, if you choose to do so.  I love shopping at those websites, and I have found incredible deals on so many textbooks, regular books, and even CDs and DVDs.  Professors do not mind if you buy the required textbooks new or used, and they often don't mind if it is not the edition they told you to get--as long as it is similar enough and you can figure out the correct pages to read (page numbers often change between editions).