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GMAT books
By an Amazon.com customer
Kaplan GMAT 2008 Premier Program (w/ CD-ROM) (Kaplan Gmat (Book & CD-Rom))Kaplan GMAT 2008 Premier Program (w/ CD-ROM) (Kaplan Gmat (Book & CD-Rom)) by Kaplan
Buy used from: $18.97
You want to start from scratch with this one.
The Official Guide for GMAT Review, 11th EditionThe Official Guide for GMAT Review, 11th Edition by Graduate Management Admission Council
Buy new: $24.39 / Used from: $13.99
Gives you many exercises, and puts you above 650.
The Official Guide for GMAT Quantitative ReviewThe Official Guide for GMAT Quantitative Review
Buy new: $11.53 / Used from: $8.00
More math exercises.
The Official Guide for GMAT Verbal ReviewThe Official Guide for GMAT Verbal Review
Buy new: $11.53 / Used from: $8.95
More verbal exercises
Kaplan GMAT 800, 2007-2008 Edition (Kaplan Gmat 800)Kaplan GMAT 800, 2007-2008 Edition (Kaplan Gmat 800) by Kaplan
Buy used from: $13.58
This one gives you those extra 50 points.
Cracking the GMAT with DVD, 2008 Edition (Graduate Test Prep)Cracking the GMAT with DVD, 2008 Edition (Graduate Test Prep) by Princeton Review
Buy used from: $14.85
This one only helped me with the AWA.
Sentence Correction GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Sentence Correction GMAT Preparation Guide (Manhattan GMAT Preparation Guides)
Buy new: $18.72 / Used from: $16.00
Really good!
Reading Comprehension GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Reading Comprehension GMAT Preparation Guide (Manhattan GMAT Preparation Guides) by Manhattan GMAT Prep
Buy new: $26.00 / Used from: $139.88
Number Properties GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Number Properties GMAT Preparation Guide (Manhattan GMAT Preparation Guides)
Buy new: $18.72 / Used from: $18.00
Critical Reasoning GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Critical Reasoning GMAT Preparation Guide (Manhattan GMAT Preparation Guides) by Manhattan GMAT Prep
Buy new: $26.00 / Used from: $18.00
Word Translations GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Word Translations GMAT Preparation Guide (Manhattan GMAT Preparation Guides)
Buy new: $26.00 / Used from: $15.00
Equations Inequalities and Vics GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Equations Inequalities and Vics GMAT Preparation Guide (Manhattan GMAT Preparation Guides)
Buy new: $26.00 / Used from: $14.50
Fractions, Decimals, and Percents GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Fractions, Decimals, and Percents GMAT Preparation Guide (Manhattan GMAT Preparation Guides) by Manhattan GMAT Prep
Buy new: $18.72 / Used from: $14.00
Geometry GMAT Preparation Guide (Manhattan GMAT Preparation Guides)Geometry GMAT Preparation Guide (Manhattan GMAT Preparation Guides)
Buy new: $26.00 / Used from: $10.00