I've checked with Amazon and have set all of mine below their prices. If you want all 6 books, I will give it to you for $50.

Princeton Review: 1014 Practice Questions for the New GRE (2nd Edition) - $10
Princeton Review: Verbal Workout for the New GRE (4th Edition) - $10
Princeton Review: Cracking the GRE (2011 Edition) - $5
ETS: The Official Guide to the GRE revised General Test - $20
ETS: Practicing to Take the GRE General Test (10th Edition) - $5
Barron's: New GRE (19th Edition) - $10