I know I'm new here but I can't pass up an AK question.
First of all, BEWARE! AK's ARE ADDICTIVE!
If, despite all the warnings, you still want one, then decide whether you want a .22 (.223) a medium .30 (7.62x39) or a big boy .308 then buy a Saiga. Absolutely, hands down, no contest, best AK for the money. You can spend more for authenticity or rarity but it won't be a better built gun. And once you get your best deal on one you can have fun turning it back into a real AK and making it look however you want. Read more here http://forum.saiga-12.com/index.php?act=idx
Unfortunately Saiga doesn't send the 5.45x39 over here so if you decide that's what you want you'll have to go Bulgarian $$$$, Polish $$$ or Romanian $$. Unless you get lucky and find a VEPR $$$$.
Other noteworthy things to consider;
parts- 5.45 or .223; could be difficult to find if needed, rare but it happens
mags- .223; different countries used different mags, they don't interchange well if at all.
5.45; They all pretty much work in all rifles.
7.62; They all work in all rifles.
One last thing, make sure whatever you decide on has the scope rail on the side and the sights aren't canted (not a problem with Saigas but has been on Arsenals, WASRs, SARs, Yugos and anything else built by Century).
Good luck!