If you volunteer then they'll let you do a course for free (or at least they used to).

They get some good people running the courses. I did the wind turbine one, and they dragged Hugh Piggott all the way down from Scotland to take it. The guy's rather gifted with small installations, and I got a lot out of it (for free!).

Kammer x

PS. The CAT shop is rather good as well, especially for books.