A word on gunshows.
Caveat Emptor or "let the buyer beware" is the rule, especially when buying AR 15 rifles of any manufacture.
For the most part, AR's are plentiful and available in almost any size, shape, and flavor. You must be very careful when shopping, though--there are some pitfalls to avoid.
I don't know how familiar you are with the AR15, so here goes.
First of all, be brand conscious. To my knowledge, the good ones out there are:
Colt
Bushmaster
Armalite
DPMS
Olympic Arms
in no particular order or preference.
Be aware of the offshoot (generic) names, too. For instance, Eagle Arms is the plain vanilla version offered by Armalite. The old service mark SGW can still be found. It stands for Schutzen Gun Works, which was started by Bob Schutzen, president of Olympic Arms.
A good non-mainstream AR, from what I've heard, is American Spirit Arms.
Of course, you have the high-dollar customs that you normally won't see at a gun show:
Les Baer
Fulton Armory
Clark Custom
just to name three.
Be very observant for the ubiquitous hand of "Bubba"--it seems that almost every jackleg gun plumber in existence buys a set of vise jaws, a forend wrench, and presto! He, too, can build AR 15's!!!
I ran into a specimen of a B16 (Bubba'd AR 15) at a Lakewood gun show. Seems the guy was so anxious to sell a post ban upper that he put a muzzle brake on a post-ban--BY WELDING IT ON!!!
(I sure would not want to fire that thing!!!)
Also, be very aware of the law concerning post and pre-bans. Don't fall for the "Hey!! I have a pre ban receiver for sale!" It won't do you any good unless it was assembled into a complete rifle.
If you wish, and if you have some rudimentary know-how, you can build a Frankengun. I took an Oly Arms lower, a generic parts set for the lower, a long A2 buttstock with its attendant parts, and a complete Armalite A4 upper. I now have a super dependable AR that I use as a duty rifle. It's so accurate that it's scary. Very nice gun, and all for a total of about $750.00.
Bottom line--be very careful at the gun show. You can get good bargains--but you can also be ripped off in a hurry. If you want, PM me for more info.