I am new to AKs as well and when I was looking I looked long and hard and ended up deciding to buy a Romainian SAR1 AKM. The SAR1 is a post ban AK that will accept any double stack AK mag and it is the cheapest option out there for a decent quality beater AK.
As for mags, buy a bunch and try them for yourself. I stocked up on mags as AK mags are still being imported and the prices are cheap. I have a small collection of 20, 30, 40, and 55-rd stick mags plus several each of the 75 Chinease and Romanian mags. Every mag I have ever tried in the AK works so the only mistake you will make is not buying them while they are cheap!
As for pre-ban vs post-ban, I agree that an AKM looks much better as a pre-ban BUT I am not willing to pay that premium. My answer has been to buy the cheap post-ban AK for now and I also have two Ohio Ordanance AKM receivers plus a couple AKMS Parts kits (1 Romanian & 1 Polish) that I will build as pre-ban style weapons (underfolder stock, threaded barrel, bayonet lug) if the crime bill dies without renewal next year.
Oh, SGN is "Shot Gun News"
This is a good site for info but you should also read the old posts here...
ak-47.net/With particularly helpful pages for what you want to know...
ak-47.net/ak47/index.htmlGood Luck!