LOL funny post but I had been looking for the same thing. In my research I found that CastleDental, a chain, has cheap whitening. It's a chain and they have a million locations across the states.
I paid $300 or so for the tube and the mouth piece which is supposed to be almost better than the in house procedure. Also, the tube lasts forever. I will probably be able to use for 1-2 years before I run out. once every 4 months or so.
OR, if that's too much the whitening strips DO work but they are a pain to keep in.