Art of Problem Solving Bookstore
http://www.artofproblemsolving.com/Store/index.php
Art of Problem Solving Online School
http://www.artofproblemsolving.com/School/index.php

I'd like to brainstorm about all the various pros and cons of working through an AoPS book versus taking an AoPS course. (I'm trying to make the conversation general, so this applies to all levels of books/courses, and to people in all circumstances.)