Examples of covers I've done for various clients with varying input from each.
Rates generally follow my normal commission pricing but are just a bit more since text and layout are involved.
Depending on the amount of detail, a full cover takes at minimum 2 weeks. Personally, I deliver a sketch first to the client and send an invoice once it's approved, and upon payment I will then work on the final draft.
Covers are for online platform use, so like Tapas, Wattpad, RoyalRoad, etc, but I can design for any sort of dimensions electronically or physically. If one plans on self-publishing with a cover I create, then I request that one buys the copyright to the cover image, which is an additional fee.