I am an artist as well as a writer and I am commissioned frequently to create covers and art for the interiors of books. Here is an example of a digitally painted cover. For something like this, I charge 250.00. Whether you are traditionally or self-published, have a print book or an ebook, your cover makes a world of difference. A bad cover will not sell your book. Having great cover art will mean book sales and readers will take you seriously.