A couple things! I hadn't started putting a sell posters because I need to get a few things done.

1. Make an official business
Which allows me to get the services of a...
2. High Risk Credit Card processor
This allows me to sell adult content
3. Finally set-up a website
ill use a merchant website service so I can take code that is already made and secure and pretty it up

As much as I like posters, I think its a much harder sell, since people arent likely to put up adult content on their wall. So I'll switch to spiral notebooks. I found decent quality third party inks. So it reduces the cost of art from super premium poster level, to magazine page level.

So finally I'd let artists sell portfolios, artbooks, sketchbooks. Magazine paper for admiring art, but people can pay more to get sketchbook paper so they can use it as a coloring book.