For SAT, here’s a deal that can’t be beat: The College Board has partnered with Khan Academy to offer FREE test prep. You can also download a free smartphone app for daily practice. If you’ve taken the PSAT (a kind of practice SAT given to 9th, 10th, and 11th graders), your College Board account gives you individualized help based on your areas of strength and weakness. Start exploring the options at http://sat.collegeboard.org; click on “Practice.”