I'm sure the Romy defenders will show up, but I'd say to spend $550 or so and get a good one.
ETA: Wow, I hadn't checked prices in a while. I went over to Atlantic's website and looked around, the $550 AKs are now $650-850. Consider a Saiga conversion (made by Izhmash, the real AK maker), a Lancaster, Vector or Bulgarian. Some would say Yugo, though they generally don't have chrome lined barrels.
Go over to ak47dotnet/ar15dotcom and read up in the AK pages to learn about the different makes:
http://www.ar15.com/forums/board.html?b=4
Personally, I don't like cheap AKs, though some say that's what the AK should be... hence Romys and such. I have a Russian one and a Bulgarian, both quality firearms; both are accurate and run like tops. I'm not a fan of the slant brake/compensator, I prefer a muzzle brake or flash hider, or nothing at all.
For caliber, 7.62x39 is of course the standard. Ammo is cheaper than .223, but more expensive than it used to be. .223 would be your best choice for availability down the road. the 5.45x39 is still cheaper than the other calibers, though I'd say to buy it cheap and stack it deep while you still can. Much of the cheap 5.45 out there is corrosive, so you'd need to clean the gun right after use. Any AK should happily digest the steel cased stuff, so no worries there.