deviantART.com

One of my favorite art sites, deviantART.com, has enormous amounts of digital art and photography. The site allows you to sell prints through them for free, and even handles the creating of the prints and their shipping. It also allows artists to put up galleries and seek commissions (also for free, but you can pay for a membership and get more benefits.)

One of the features I use most, is the gathering of stock photos. If you go to the main pages and select catagories, then resources, and then stock, you will find a host of free pictures and art. Each artist that posts stock is allowed to set their own terms for use. Most of them just want to hear about your use of their work, but some want to be credited and linked back to their own site. The terms should be easily viewed by clicking on the artist's name and going to their journal.

DeviantART is also a good place to pick up line art, which is good for coloring. My roommate uses the line art to practice digital coloring, while I just print it and find my crayons.

All in all, I completely reccommend deviantART for the new artist to start selling, for inspiration, or just to pick up a print that is unique and beautiful.