I know several authors who do not create hardback or paperback books, but create pdf file books online.
If you do so you will need the artwork created for your ebook cover.
I just finished my ebook called Ecovers Using Free Tools
You can get it here free.
It is a step by step tutorial on how to create your own ebook covers.
I am working on the video version right now for those who need a visual.
I hope this helps anyone who needs to do this and is trying to keep their budget down.
Have a wonderful week,