The book required for the course is by Freeman (UW prof who also wrote the biology book) and it is a new edition. A new copy is $90 and if you are lucky enough to get one of the few used ones, it is still $70. Do you really want to pay that much for a book you only need for 3 months?
I have a older version of the book (v2, not the newly required v3). I used it this last quarter with no problems. Some of the chapters have different numbers than the current version, but there is no new information that the class requires you to know that v2 doesn't have. The book is in good shape with minimal highlighting. I can't sell it to the Bookstore and I want to be rid of it. Anyone who wants to pay $25 for it can have it. (I figure you will lose more than that in buyback, even if you start with a $70 used book.)