You're more likely to be crying when you're walking out the door. You will have seen table after table of the same plastic guns (Glocks and ARs), with almost no antiques, exotics nor collectibles, most all at prices that will leave you underwhelmed.
Don't buy anything for which you don't know the market price. A couple of the established dealers will have good prices, but then you'll find the guy with the surplus Sig P6 who insists that $450 is a great deal.
Don't forget to buy some beef jerky.