Well, I'd be interested in seeing what others suggest, but good, musical subs (as opposed to simple, theater appropriate subs) tend to cost more than the price range you have given. I would look for a used Rel, though again, you are going to have to increase your cash outlay for one.
Also, a key question is how big is your room? It is hard for people to offer sub recommendations with out knowing that.
Also, a key question is how big is your room? It is hard for people to offer sub recommendations with out knowing that.