Before I answer that question, I need to review what it takes to produce a great book cover. There are two people traditionally involved in bookcover design:
• The illustrator/photographer who provides the artwork for the cover.
• The book designer who pulls together the art and the text/typography into a beautiful, eye-catching design. Some books can get away with just design, but these tend to be self-help trade books, not novels.
How much should you expect to pay if you hire a designer to design your book cover?
It is reasonable to expect to pay anywhere from $500-1600 for a custom design.
Following is a list of what elements factor into the price range.
• If you can supply the art (photo), expect to pay in the lower range of that scale.
• The higher price range is for a cover that needs original illustration or photography.
• The mid-range would be for a cover that utilizes stock photography. Higher prices reflect higher-priced stock photography. The higher priced photography has fewer users, so you are less likely to find your image somewhere else (embarrassing).
What you should expect for your money:
• Any cover should include 3 comps/revisions. It is my experience that most clients need revisions: what amounts to 3 sessions with the designer.
• All covers should include a digital Ebook version, formatted in 3 sizes for Ebook cover, advertising and icon (postage-stamp version).
• If you provide the artwork (you have to have the rights to this artwork), then you could probably fit into the lowest price, because I would then be just designing your book, not illustrating it.
Remember, that the designer of a book cover is responsible for the front, the back and the spine. Also, she is responsible for the color fidelity, and this requires a hard proof in all cases. Never does the design on screen match what is in print, and all printers are unique. I know, for example, that Lightning Source tends towards magenta in the final print. (CMYK stands for Cyan, Magenta, Yellow, and Black; all color prints are made of all 4 colors).
I highly recommend that any publisher use a professional designer for their book covers, if not for the interior. After all, the cover is the most important selling tool that you have as an author.
There are many things that a designer knows that can make your process go much smoother. In the long run, unless you want to go to school to become a designer, it will be cheaper to hire one.