All the nice doubles for under $500 are over on that side counter with the Holy Grails.
A Stoeger Uplander with double triggers and extractors is a pretty reliable gun. Not a Purdey, but they work. Popular with that Cowboy set and they are hard on guns. If you get the single trigger model with ejectors - all bets are off. If you go cheap keep it simple.
A Stevens 311/Fox B is also a good serviceable gun and I think they handle a little bit better than the Stoeger.