Well they didn't have bulk when I started shooting either. Cheaper ammo (i.e. Winchester Wildcats, Federal Lightnings, Remington T-bolts, etc) came in little 50 round boxes and we bought it in bricks (500 rounds). Same cheap kinda ammo, different packaging. So while we didn't call or refer to it as bulk it was essentially the same thing.
Correct me if I'm wrong but what might be called hunting or target ammo wasn't nearly as available as what we have today.