It all depends on what you want. Other than fit and finish, looks basically, you probably wont see any real difference shooting them.
The only difference Ive seen shooting wise, has been with US made/built guns. Mine, and those Ive shot, were the least accurate of any of the AK's Ive shot. Then again, its been awhile, and maybe they are starting to catch on.
I have a SAR1, a WASR10, as well as a Krebs Saiga conversion. At the time they were new, I paid $325 for the SAR, $350 for the WASR, and $700 for the Krebs. Both the SAR and WASR shoot just as well as the Krebs, even with the SAR's slightly canted sights. I did have to swap out the SAR's trigger due to slap, but that was a common problem with the SAR's. Most of the US made compliance parts were (and probably still are) junk. That part of the equation might make the higher end guns like Krebs worth a little more. The WASR was a little more refined than the SAR, and had straight sights and no slap. I have yet to see a WASR with canted sights, and I believe it was mainly an issue with the SAR's (Ive seen some that were "really" bad), and corrected within them.
As far as prcies for ammo and accessories (guns too for that matter), youre coming in on the wrong end of things here. Back when everyone hated them, everything was cheap. I stll have cases of Barnaul 125 SP's that I paid $75-85/1000 for, and some old Norinco steel core that was $100/1200 (for awhile there, the steel core were bringing $1 a round on Gun Broker). Brand new Bulgarian mags were going for 10/$75.