the vender you saw with the Saiga-12 couldn't sell it period. it was not of legal length. a batch of Saiga 12's came in from RSR with barrels below 18". i was there set up next to him.
the austin show isn't as good as the DMH show from a buyer's perspective. Bachman isnt there to sell things at dealer cost to run out other dealers. personally i like it that way. most ARFCOM buyers disagree and say bottom dollar is king.
that may be true until you need someone to give you customer service or maybe even repair the item you purchased at rock-bottom pricing. Bachman, AJC, Schramm's, etc, do not repair guns.
ask them to fix the gun you bought from them. they will tell you to send it to the manufacturer. they don't have time for you after you buy the gun unless you are there to buy another one.
there are some dealers out there who may charge a bit more, since they aren't buying 100 guns at at time. but they may either have the knowledge, or have a business relationship, with a gunsmith who can repair your gun if something goes wrong with it
also, they may impart some knowledge on the guns they sell that others may lack in expertise. you can ask some of the big dealers if their barrels are chrome lined, their twist rate, the type of trigger in the gun, whether or not it has a forged or cast receiver, etc. the big guys sell alot of guns and thus don't have the time to know every gun they sell inside and out.
they also kill you on trades. they buy new guns for so low they can't give you alot for your trade. i had a friend with a 95% Sig P225, box, 2 mags, and night sights. AJC offered him $300 in trade.
just my two cents as a small dealer.