It doesn't have to be a high-dollar to be reliable, just made of halfway decent parts, properly assembled, and (ideally) have some oil shot in and around the bolt carrier now and then. A DPMS or Olympic Arms rifle with a properly torqued and staked gas key and staked castle nut is probably going to run very reliably, even if it doesn't have quite the durability of a BCM/DD/LMT/Colt. And the best magazines (PMAG's) aren't expensive at all.
If some cut-rate AK builder wasn't bothering to pin the gas piston to the bolt carrier in the AK's it made, causing the gas piston to come loose and jam, few would blame the AK design for that; they'd be more likely to blame the lazy, out-of-spec assembly. Ditto if an AK were made with weak, substandard parts that even Norinco would be embarassed to use, or if someone's AK jammed because they were using worn out magazines with damaged feed lips.
I think you could probably get a very reliable AR for under $800, if you shop carefully.