redraif good luck on finding a semi-auto for sale. At least one for a fair price. I have heard of Hi-Points selling for $500-600 dollars. The Beretta, who knows.
Call before you go. Some shows are being canceled because vendors don't have anything to sell. Don't worry about the background check. They will explain it to you. Here is a site with all the gunshows. Just click on your state.
http://www.gunshows-usa.com/