How much do graphic designers, in the US usually charge ,on average, to do covers for e-books?

I was just wondering as I hope to self publish a book someday. For this one book, I would maybe like the book cover to look like an album cover and have the protagonist's name on it. Thanks to all who reply.

Great design resource

100 Things Every Designer Needs to Know About People (Voices That Matter) Submitted April 27, 2019 at 08:21PM by empress_of_pinkskull http://bit.ly/2Vwt9Yq