GRE/MAT prep.??

What books/ study materials would you all recommend for preparing for the GRE or MAT (I plan to take both)? Did anyone take the Kaplan or Princeton review course?? They are so expensive, so I am wondering if it would be worth it or if I should just study with practice books. I am a complete math retard, so any math review materials anyone could suggest would be awesome. I took the GRE a few years ago before I went to my BSN program and really did not do so hot on the math section, so I would really like to improve my score. Thanks guys!!