Ten years ago, the shows were how you saw what was new, and could handle some goodies, rather than look at them in G&A or whatnot. The prices used to be 5-10% off of what you could find in the stores. Now it seems that most dealers add 10% for doing YOU the service of bringing their wares to the show! I do most of my shopping on the net, particularly right here on ar15.com's EE. I'll SERIOUSLY buy from Jerky Hut, and ammo from Miwall, cleaning kit supplies, and at the Trop show, some glock mags ($24/each). Once in a while, a bargain is there, but rarely. My best find was a BHP Practical with 1 hicap (2 years ago, when hicap meant something) for $295.
If i were to have a booth, and was a shop with armorer, i'd sell the usual guns & stuff, and offer:
1. glock repair (saw this at SAR show last year, thought it was a great idea)
2. sight installation
3. AR barrel work possibly, to take advantage of the changeover
I still like going to the shows, again to touch and see. Seriously, you could do worse with $10/11/14.