Kaplan:

• MCAT Biology Review (3rd edition): $15
• MCAT General Chemistry Review (3rd edition): $15
• Get Into Medical School: A Strategic Approach: $10

The Princeton Review:

• MCAT Organic Chemistry Review (also includes 2 full-length practice tests online): $15

Other books:
-McGraw-Hill's 500 Questions to know by test day, General Chemistry: $10
-McGraw-Hill's 500 Questions to know by test day, Biology: $10
-McGraw-Hill's 500 Questions to know by test day, Organic Chemistry: $10
-REA's Your RX for the MCAT (has 6 full-length practice test and CD included): $15