Ah, capitalism! Someone sees a market for something and then acts to fill that need at a healthy profit for themselves. It works so well (on paper)! A personal hobby horse of mine is what often seems to be a failure of otherwise fascinating and detailed fictional worlds with meticulously developed supernatural or pseudoscientific powers failing to take the profit motive into account.
My most often cited example of this is the long suffering Peter Parker. The poor guy barely covers rent in a thankless job doing freelance work for a borderline yellow journalist. The psychological reasons for why he continues to punish himself year after grueling year have been well-documented, but still, I’ve occasionally wondered why a man of such scientific skills doesn’t get himself a better job. This is a guy who over what was essentially a long-weekend invented an incredibly compact liquid substance which when exposed to air would instantly harden into a powerful adhesive which would furthermore dissolve all by itself after a few hours. Consider the potential non-lethal uses of such a weapon in the hands of law-enforcement agencies as a legacy for poor martyred Uncle Ben. If you were willing to be a bit more mercenary, consider the industrial applications. I recognize that he has a deep need to do personal hero work, but it just seems that having a decent financial base to fund your vigilante efforts above the poverty line might make your life a little more bearable (not that it seems to help Batman much).
Still, an example of a well-thought out economic plan in an unusual setting always makes my day. Here are a few examples, though I’m hoping other people will share a few more.