Eh, maybe I'm just an outlier but I got a 1370 in 1997 without really trying, let alone actually spending money to prepare. I'm also a 100% product of public schools.
The secret to standardized testing is fast reading comprehension. I've always been a fast reader (without sacrificing comprehension). It frees up time to go back and really spend time on the tougher questions that just isn't available if you have to spend a long time just reading the question (it's more than just in the reading comprehension section, since you have to actually read every question to get through the test).
It's basically "Write a generic 5 paragraph essay using memorized argument flow."