It does appear that AIMSurplus is currently out of 7.62 x 39 SAR-1's ... see
http://aimsurplus.com/acatalog/AIM_Rifles_1.html
The price on your auction is indeed a
little steep. Also, I don't have much experience with SAR-1's, but my impression is that this is one rifle you're best off to buy after inspection. I looked one over once, and the front sight was canted. The quality appears uneven, so look it over hard, and make sure you've found a good specimen.
Some other web sites to help you:
http://www.shotgunnews.com/gunad/ -- ads in Shotgun News
http://www.gunsamerica.com/ -- one of the better auction sites, from what I've seen.
http://www.ak-47.net/ -- great source of all kinds of AK information.
http://webarmory.ixworld.com/manuals/akmanuals.html -- this guy does a real service by providing all these manuals.
http://www.tapco.com/store/ -- good source of mag's and parts.
http://www.k-varcorp.com/ -- another good source of parts.
AK's are a bit confusing, because there is such a wide variety -- AK-47.net can help you understand the differences. I've heard the best things about the Polytech's, Bulgarian SLR's, the Russian VEPR (from Robinson Armament) and the Gordon Technology offering. Many folks appear to be more enthusiastic about milled receivers.
Now, after you get your AK, you'll start wanting a .308 battle rifle ...
Good luck.
Regards from AZ