Did we really need two threads started less than a day apart for this?
I know a number of users swear by Cinegobs. It's free but the learning curve is a little steep, and as far as I know, you can't layer several keys of the same type onto a clip. If you don't know what that means, suffice to say it's tough to rescue a clip if you didn't light the background properly. The After Effects plug-in Keylight is far and away the best keying software I've used, but even the student price is probably well out of your price range.
Check the thread I linked to for some links to some older threads on the same topic, as well as some info on the proper setup.
With all due respect Noodle, I don't want you here. - Ratboy Productions