I'm doing the course, but I'm primarily doing it for the Kaplan review book that comes with the course. Unlike the Kaplan DAT book, this one is not available at bookstores and other retail outlets.
It used to be for sale frequently on eBay, but Kaplan has since cracked down on the sale of their special products, so unless you can get one from an upperclassmen or under the radar, your best bet is to fork out the $500. In my opinion, the book alone is worth that price, and you should be able to sell it to an underclassmen for $200-350 anyway.
That NBDE I book does an excellent job in most subjects that are tested, and provides a solid base for all the subjects.
