There is a great selection of AK's over at Sooner Guns on Mingo. I bought a great WASR 10/63 from Mark a month or two ago. You just have to inspect the firearm to see if it has any mag wobble, canted sights/gastube. Luckily all the ones I've found over there have had none of these issues. They run $469 I believe.
Good question, I've been musing around the idea of getting an AK but cost and quality are my concerns as well. I've just about decided to go with a Saiga sporter and convert it, but I do not fully understand the rules for 922 (r) COMPLIANCE.
It would be fun to convert and I think Saiga makes a good rifle. Now as far as cost, I have not put a pen to it yet.
For the money you will be hard-pressed to find a better AK than a Chinese Mak 90 or NHM 90, especially now that they've gone down in price. Their quality is superior. 91's are the same, but with longer barrels. Some are milled, but expect to pay more for them.
At gunshows, they still carry a premium, but they are also more negotiable than they were a year ago.
I got to shoot a milled mak 90 at the shooting academy this past weekend and it was noticeably nicer than my WASR. I love my WASR for what it is and the price I paid but damn that norinco was nice.