Ah, the life of the writer and artist -- one I know well. By the time you figure out the cost (hours) of research and creating the article/painting, it turns out you're working for much less than minimum wage. If you actually priced the article or story or artwork at minimum wage plus expenses, original pieces would cost thousands of dollars apiece. And while the very famous can get away with charging those prices, folks that aren't famous can't do that.

About 20 years ago, I was talking with some artists in my field (science fiction and fantasy) and they pointed out that most people buy artwork to have an affodable decoration for their walls. In most cases, they'll spend under $100 -- most artists can't afford to sell for so little. The trick, therefore, is to do prints so that one effort can be sold a hundred times over and you have a good stock to send to any show.

Prices depend on the type of print.

The trick is doing a piece that you like and can stand to sell for several years.