I found a blog post today that directs you to a site so you can make your own flat book cover into a 3D cover.
I tried it with my Earn Money as a Lab Rat book. Here is the 3D cover I made. It was so quick and very, very easy!
Check out my book on Amazon here, if you'd like: Earn Money as a Lab Rat
Here's the link to make your 3D cover: