I'm also on foundations 3 at this point and love the system. I combine it with Anki to reinforce the retention of older material, and I find the price very reasonable for something that helps me learn math consistently.

As for the price, I see people mentioning text books as a cheaper alternative, but Math Academy includes review work, tests, and retakes when necessary. It takes care of the organizing and evaluating that is related to but not the same as the learning. You can focus on being a student, without having to also be the teacher.

I would love a full depth, accredited system that didn't cost thousands of dollars.