Nothing comes free these days here is Princeton's paid preparation material
http://www.princetonreview.com/Compare_Our_GRE_Online_Programs.aspx?uidbadge=
Gre is a tougher test compared to TOEFL exam I would recommend that a person first takes Gre then Toefl exam so he has a better chance of getting higher score at Toefl with improved vocabulary. I would recommend that one buys Barrons GRE for GRE preparation because Kaplans GRe book doesn't have the high frequency words mentioned in the barron's book.
