<p><a href="http://www.betterthanthebookstore.com%5B/url%5D">www.betterthanthebookstore.com</a> is pretty awesome in terms of buying cheaper than the Penn bookstore, seriously. Half.com is also REALLY good in terms of competitive prices for books. It also helps to ask professors whether or not older editions are suffice for the course, that could save you tons.</p>