I put together lectures for a community arts group. One of them was on selling on ebay and the web. I had two painters and one photographer. They all had various degrees of selling on the web from beginning to advance.
One of the things that struck me was the market and marketing.
This one artist said he painted "Rain" paintings i.e. people walking and running with umbrellas and so forth. His belief was this would be a natural seller in his home territory of Portland, Oregon.
But, it wasn't. He sold more work to folks in Florida. I guess they miss clouds and rain down there. He would have never guess this until he did the online selling.
Then, this same artist started making small one of kind paintings on ebay. These would go for a small price. What he found was that the buyers would then go to his website and buy larger paintings or commission him for other work.
This fellow isn't making barrels of money but he's enjoying himself and keeping out of his wifes hair. He also said that galleries were not working for him and he had done the art festival thing and that was too hard for him as well.
My two cents for what it is worth.