Hey, I passed my PMP exam one week ago on the first attempt.
My main lesson learned is, that buying too much material is not necessary. What really helped me was a preparation course offered by a local PMI chapter (12 sessions for round about 100 €).
There we worked through the whole PMBOK, discussed the content and made example questions. Additionally I solved questions on examcentral.net, where you have about 1,000 questions for free if you register on the site.
Furthermore there is a free document on the internet that is called Edwel's PMP Exam Prepbook. Again you need to register and get a PDF document which coveres all topics. Furthermore it gives hints for the exam and at the end of every chapter there are 20 - 25 questions.
I purchased the PMP Prepcast as well, but a lot of things mentioned there were also discussed in the preparation course.
Hopefully this information is useful for you on your way to the PMP.
Best wishes
Christian Keuler