Disposables. Blister packed, already loaded ten round capacity nines that you can't reload again.
It'd take care of a lot of the new people who buy a gun for self defense, and don't train or practice with it, just put it in a drawer against some future need. No need for them to buy ammo they won't use.
10 rounds, so you can sell them everywhere, regardless of mag capacity laws.
Nine MM, so everyone can shoot it well. Heck, make .40 and .45, too if you want. Put a safety on it to make those people happy.
An enclosed plastic handgrip with nowhere to put more ammo when you run out, in a sealed package for safety.
Single or double column, basic sights. Fairly heavy pull, maybe 8-10 lbs.