1. *Black powder* is relatively easy to make, assuming one can find the sulfur and saltpeter to mix with the charcoal, but that’s a far, far cry from what is used today, how it’s manufactured, even down to humidity control of the production plant and the shape of the finished product.
In other words - and as any chef will tell you - you can give any hack all the ingredients to the best dish on the planet, but relatively few will do it well. That’s the nature of any form of chemistry, whether cooking gunpowder or meth or food.
Even more importantly, last I checked, people don’t get physically addicted to gunpowder. In fact, after a few lose limbs, eyes, or lives because the bullet blew up when fired, you’re going to find that while there will be a black market for gunpowder, it’s going to be *nothing* like for addictive drugs.
And again - if ya just gotta shoot and don’t want to spend so much, just go to your local gun range and purchase (and use every bit of) your ammo there.