Samantha,
The simulator for this course has over 2000 questions and is robust enough to prepare you for the test. I wouldn't pay for another one if you're already paying for this one.
It will also explain your correct and wrong answers and give you a scoring of each domain to show you your weak points. Also, it will show you the percentage chance you have to pass on the first, second, or third attempts.
The test is hard, but not so hard that you need to over prepare and waste additional resources. If you want a cheap simulator, I believe PMP for Dummies has a full test in it also while remaining cheap.
In my personal opinion, you don't need to try too many other simulators to pass the test.