Review Books for Boards

I haven't yet started studying seriously for Boards, but I have started collecting review books. As I'm starting to look into how to study for the USMLE, I've become sickened by the ridiculous amount of commercial prep materials out there for this exam. I really dislike this aspect of high impact standardized tests. Money should not be able to buy a better score on an exam. I'm not sure whether there's strong evidence that this is the case, but regardless, people think it is, feeding into this burgeoning industry which takes advantage of vulnerable (rich?) students. When I see thousand dollar courses run by professional companies and piles of review books and boxes of flash cards, I wonder whether I am shortchanging myself by refusing to splurge. I'm the kind of person who believes (naively?) that the coursework of the last year and half should be sufficient, that textbooks are the best source of learning, that the goal of these basic science years is to lay a foundation for understanding medicine, not for acing yet another exam. I think right now, my focus will be on using materials at the library as well as less high yield resources (texts, syllabi). We'll see.