Ebook covers are make or break.
If your ebook cover looks cheap, your readers will think that your product is cheap quality and they will be less likely to buy it.
You could cut corners and design your ebook cover yourself. But it will probably show through in the design and ultimately in your sales (or lack of them).
And let's face it, most of us flunked art when we at school. So a home-made ebook cover design will show up as exactly that.
That's fine if your whole site looks like it was put together by your 7 year old child.
But I'm assuming that you want your ebook cover graphic to look good. That you want it to look professional. Something that you'd be proud to have on the cover of a real book.
There are software programs available that claim to help you create professional ebook cover graphics. The ones I've tried might live up to that claim in the hands of an experienced user. But in the hands of a casual user like me... All I did was waste a few hours.
So for most people, it will be a case of getting a professional ebook cover created professionally.
In the scheme of things, this is a one off cost from as little as $30 on a freelance site, up to $100 or so from a professional graphic designer. So a few dollars and a few days later, you'll have your ebook cover created so that you stand the best chance of getting sales for your masterpiece.
Don't let yourself or your product down - make sure that you give it the best possible chance of selling by getting the best possible cover designed for your money.