I've started selling book covers about 1,5 years ago and had trouble getting the word out on my own. A friend recommended SelfPubBookCovers.com and after some research, I decided to upload a few covers to test the waters.
Rob, the owner, is extemely nice, very patient and always ready to extend a helping hand to a new artist, no matter the time.
Artists can decide on their own prices and only the best covers get approved. If the quality is not on par with SelfPub's standards, it will be declined.
As to date I've sold nearly 200 book covers thanks to this site and am now able to do this for a living.
Quite a few authors have told me how happy they are with their covers from SelfPub. If I weren't an artist myself, I'd definitely buy the covers for my books here (I'm also an author).