RE: slug gun under $200
You might be able to pick up a used pump gun for that. Other than that the only thing that comes to mind is one of the H&R/NEF guns without the heavy barrel. I believe they are tracker II's, I would have to look it up though. They are a single shot with open sights. They don't weigh as much as the ultra's though so they kick a bit more. Still fairly accurate guns however
You can get an ultra for a little more than 200 though I think.
Rossi may have a slug gun, but I'm not sure.
Paul