check out Tomball Pawn.  i've purchased 2 handguns there and both times they've beaten the competition by $50+ on the price and their guys in the firearms dept are very helpful.  i was in there just last month but don't recall seeing an AK47, but i'm sure they have them.   
http://www.tomballpawn.com" onclick="window.open(this.href);return false;   phone # is on their web site, they'll tell you what they have in stock and give prices and everything.
Collector's Firearms is another place that sells AKs but they're priced a bit high compared to what i've seen elsewhere.  and good luck getting someone to help you.  i went in there last month looking to get an M1 Garand for my dad as a Christmas present and asked a salesman if he could help me pick one out (i didn't know anything about the Garand).  he told me if i didn't know anything about the gun then i had no business buying one.  haven't been back there since.