Digital Sales are a somewhat hidden aspect on the Fine Art America site. Even though I knew about the feature, I had a hard time finding the exact link to post here. It was a bit of a struggle also to find exactly how to enable in the first place?
This is perhaps because FAA does not take a huge cut of the posted price. Their current "Rake" seems to be 30 cents on the dollar. While not small, it is much better than the approximately 80% they collect from printed material.
Having said all that I have never sold anything via this method even though my prices start at under $2.00 for a digital download with a Royalty Free License.
You can see most of my work here;