Depends on the age, condition, location, etc...
I bought a used (200 rounds) Bushmaster Shorty AK for $750 about a year ago. I'm in the Maryland area and new guns were about $825.
Basically, it's all about what you can get.
Check out [url]www.gunbroker.com[/url] and take a look at what people are asking.
If it looks new, I would think you could get at least $650~$700. Little tough here with the LEGP purchase at $660, and lot's of other rifles for sale.