L.B.
I helped my son run a part-time bread baking business when he wanted to earn a little money. He took orders, made the bread, and then delivered the bread. I helped him purchase pans and ingredients, which he had to pay off with his earnings. I also taught him how to bake the bread, which he was then able to do very well himself. This was a very popular business and, had he wished to do so, would have had a good ongoing business.
If your son were to do something like this for an extended period of time, he would probably have to do the appropriate licensing through the city and state, however.