I did not purchase additional materials - I studied using the PrepCast and Exam Simulator.
I will note that I did not pass on my first attempt, but I passed 3 weeks after the failure. Over the course of those three weeks, I focused my full attention on the Exam Simulator through the Learning Quizzes on the Domains I needed improvement on. I cannot stress enough how helpful this was.
You gain knowledge via the PrepCast and the Exam Simulator, but you will only understand the application of that knowledge upon utilizing the Learning Quizzes. To really take advantage of the Exam Simulator, read everything fully (questions/answers/explanations) whether you responded correctly/incorrectly.