Yeah, gotta be prepared for those wild dog packs!
Anyway, all my AK stuff is in 7.62 x39. Either .223 Saigas, or WASR-3s seem to be the way to go in that caliber. I have not looked into prices much lately. I have heard that the AK in .223 can be less reliable due to the non-tapered casing of the round, and that it might be better to stick with the AR platform in .223.
Unless you're really committed to .223 / 5.56, another option to consider would be an AK-74 in 5.45. Cheap and plentiful ammo (for now :)), and a decent rifle from e.g. Century for $400...
If you want to read more, there is a forum called Warriortalk that includes an extensive section on all aspects of the AK...
Here's a sample thread related to your question.