Revs

Hi people, I have used the Official Guide and Barron's for preparation. I am not worried about any of the concepts in math. But I am frantic for more practice tests and questions. I have just 5 tests. I looked at all the other books. Compared to the Official guide, none of the books have questions on probability and counting that are of the right degrees of difficulty. So I am not able to make up my mind which book or online sets to buy next. I have about 2 weeks - and all I wish to do now is take tests every day till exam day. The reviews for 800 score.com are mixed - the ones I read on forums here. Then there is the Princeton - but it's costly and I am not sure it'd be worth it if the CD doesn't work or something :( Any suggestions? I am on a bit of a tight budget too. But if it'd be worth the expense I would spend it. Thanks!!