If you go on Ebay you can buy some turbo jam dvd's by themselves. If you just want to tone up, you don't need to be on a "program" like it is when they sell the whole thing in a big package. I like Turbo Jam, Billy Blanks Tae Bo is fun too, I also have the 10 minute trainer DVDs, and just about every one from Jillian Michaels. Just build up your library cheaply by buying on ebay, at garage sales, etc. That way, once you get bored with something, you can move on to something else. The Jillian Michaels 30 day shred is awesome. You sweat like a pig but it's only 1/2 hour long so it's quick & easy. It also comes highly recommended by everyone.
You can also rent from netflix so you can decide which ones you like enough to spend the money on.
Hope I helped a bit!