Combloc steel AK mags are well-nigh indestructible, unlike AR mags which were originally designed to be disposable. As a result, a handful of steel AK mags will probably serve you the rest of your life.
I think I have about ten mags for mine, 8 of which are "serious" mags (Hungarian 20-rounders, Romanian 30-rounders, and a single Romanian 40-round RPK mag), and 2 are reduced-capacity hunting mags (one 5-rounder and one 10-rounder). I use the 20's the most, with the 30's in second place; the RPK mag is a little on the heavy and awkward side.