WASR-10 for ~$500
Saiga and convert yourself for ~$500-650 and a few hours of hands-skilled labor
Norinco for about $700 if you find a reasonable price on them; most sell for more, though
Yugoslavian M70AB1 or the AB2 underfolder for about $675-750
The WASR is a good, basic beater rifle
The saiga is gonna be the best bet because of its quality and overall fit and finish compared to other AKs (it's still an AK though, not a beauty queen, but they do have a much nicer fit and finish). plus, it's an as-close-as-possible real-deal IZHMASH Russian AK. The only downside is that you'll have to convert it yourself. I say this because most of the 'affordable' pre-converted Saigas out there are shoddy at times, although they will be in your price range and can still be fixed up. But all in all, converting yourself is going to give it more consistency, teach you the joy of the AK, and save you way more money.
The Yugos are overbuilt tanks with really nice worksmanship. They do not have a chrome-lined barrel, so be wary and give the barrel a bit more attention. The lack of chrome can make it very accurate (for an AK) though. Another thing to keep in mind is that they are antiques and are going fast. They have doubled in price in the past two years (when I first got into guns you never saw them for more than $400, and WASRs were still $320).
The Norinco ones are very nice as well, but you'll be at odds finding one in your price range.
All of the AKs out there will shoot about 3-4" moa. You may get a little more out of the Yugos and Saigas, but overall you will not be out-shooting any ARs with one.