Morphing Green Screen

Hey,

I checked out several other forums on here and else where but none seemed to be too helpful. Is there a quick and dirty way to do morph that's free?

Here's how I what I want to do: I have a green screen interview and the subject needs to be cut up. Luckily it was shot with higher resolution than we're outputting it to, so we can scale up a bit without too much loss. I think if it's quick and dirty the motion blur on the scale up will cover the dirtiness/mask the edit. So it can be dirty, and I'd really prefer something quick so I can get the job done under budget. Any suggestions?