Look at the top of the page, and there is a tab for "Classifieds." You can post anything you have for sale there, and a posting will show up on the discussion forums (new posts) linked to the classified ad.
Not sure on forum rules, but your best bet may be just use this thread, post pictures of your paintings and ask people to PM you if they are interested to keep actual wheeling and dealing off the forum. I know I would like to see some of your work!
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