I would recommend checking out:
I think they have better quality work posted than most other sites. And, they have various contests throughout the year. If you're looking to sell work in a community online, I'd recommend:
Zazzle (which is very time consuming to put a page together)
Cafe Press (Pretty much the same as Zazzle, but has a longer history)
Etsy - This is a really cute place for cheaper hand made stuff. They did have original paintings, however prints were selling better. There's a lot of cool things on this site that may be cheaper, but I noticed artists selling more in bulk. This seems to be the breadwinning site. They also have community forums.
Good luck. Whatever you do - it takes time to build the site and to drum up conversations.