Yes, exactly. It was through a neighbor. He had a functioning trading card business to start with, I sold my first order to him, then his clients started asking for prints.

I'd argue that's a "business", there were sales, supplies, a bottom line, et cetera, it's just the front-end part of the business was in collaboration with someone else.

It was pretty random, but there's all sorts of other 3D printing businesses like this for D&D supplies, tool attachments, et cetera.