Will- I have always had great experiences with Gary Nucherino at the Nationals. He has pre-war cards at decent prices and is willing to negotiate, especially if you buy multiple cards. There are several dealers who are very cordial and will deal with you, it's usually a "walk around, examine prices, see if the dealer will bend at all" situation which each collector has to find out for himself. I remember when I first started going to Nationals I just paid whatever the pronounced price was if I wanted a card but after hanging around with some of my Net 54 buddies and watching them haggle prices down, I started it a little myself and it paid off. Good luck and have fun! I think the best part of the National is not the cards but the comeraderie with fellow collectors.
tbob