Usually when I go to a puter show, I ask the seller if they do the refunds. Usually they're a little bit of a distance away, but they still honor the vendors warranty
I sometimes go to the ones in this area (if you're willing to drive 45-60 mins you can go to one nearly every weekend lol) The ones around here the market pro computer shows, not too bad...
Do sometimes get good deals, but do make sure you know what you're getting... they are salesman after all