There is a scholarship for the PSAT if you're interested, called National Merit. I don't know so much about it, since it only applies to Americans (I'm Canadian), but I wouldn't worry about it that much. As for studying for it, I took my PSAT without preparing for it at all, and I got a good score (>1300) on it anyway. Whether you study for he PSAT or not doesn't really matter.
There are tons of study guides/books to the SATs, which I'm sure you can borrow from a library. satpractice.org is pretty cool, as it's tailored to give you practice problems in the areas you need help in the most. It's free too.