ThriftBooks.com is a great website! I know I've said this before but I want to say it again. I've made many orders, and only today did I get a book that had a few pages missing.
It's late Tuesday night and I wrote them to ask what to do, and they wrote back within an hour and said no worries, they'll send me a new one, free of charge, I don't have to return the old one. Such nice folks!