When I bought the FALs I got 20 magazines, and have added to that whenever I can find the good, heavy, steel ones.
The AR just has the two it came with.
The AK has one 30-rounder, 4-40 rounders and a drum.
The SKSs just have the one fixed 10-rounder, I see no need to make them less reliable.
Then there's hundreds of stripper clips for the Mosins and Enfields.
When I get that Garand of my dreams, I'll probably go for 100 clips to start.