A cheap and effective way to boost your SAT scores

You don't have to pay for an expensive course or tutor to prepare for (and do well on) the SAT.  Check out Cal Newport's post, How to Ace the SAT: A No-Nonsense System for Students Looking to Score High.   I can't imagine a student who followed this system not raising your score substantially, and for a tiny fraction of the cost you'd pay for most courses and private tutors. 

And while you're reviewing your wrong answers as he recommends you do after practice tests, you should know that the The Khan Academy has worked through every question (EVERY QUESTION!) of the College Board's Official SAT Study Guide.  And you can view all of them for free.