I bought my textbooks at the campus bookstore first year only because we didn't get our schedule in time to know which books we were using. This year, I ordered online and saved over half. It also helped that some of my casebooks were older editions. Downside to that is there will probably be a new edition coming out before I can try to sell mine. Anyway, if you know the ISBN, try Googling it. Sometimes there are smaller bookstores that are selling it a little cheaper or offering free shipping. I've ordered from several smaller ones, as well as half.com, ebay and amazon. But if you're buying used, make sure you double check the condition of the book. If you don't mind highlighting, it shouldn't make a difference. But if you do, make sure the seller carefully describes the book's condition.