Its hard to beat the bushnells when you are on a budget, but for a shotgun you are going to want something with some eye relief. You could get a BSA Catseye for around 60 or 70 bucks, they have 4 inches of eye relief, but I think a shotgun scope might run a bit more than 60 or so dollars.

I have a BSA red dot as well. It works ok, not the best thing in the world but hasn't broken in 4 years. I have had it on my bow, a paintball marker and my turkey gun (12 gauge mossberg with turkey loads).

I'd look at a low powered shotgun scope myself, I think you would like it better.

Paul