As far as paying for cards at the National, I will echo others' sentiments. I usually bring a wad of greenbacks and then a checkbook for the "just in case" situations. When I sell I will take cash or a check, if the person giving the check has some relevence about them. (that last statement is what I call the "warm fuzzy" factor). I almost always wear a T-shirt, shorts and good sneakers. And the best advice is to not eat too much food at the show. Maybe a hot dog to get you by but I would not eat a whole lot....or you might not have a nice night
......regards