Academic libraries generally don't buy these kinds of books. We and other I-Share libraries may have a very limited selection of older editions, which you find by searching in the DePaul library catalog. The Chicago Public Library or your local public library will likely have a much more extensive collection of test prep materials. If you are commited to taking one of these exams, purchasing your own current edition of a test review book is a wise investment towards a good score.
Be careful before purchasing access to any online test preparation services. Friends and classmates can be good sources for recommendations.