I have the same kind of leather cover Kindlekitten has and it offers a good protection, I find. I'm always very careful with my things, but I did let is slip out of my hand once and---no harm done.
It doesn't matter what kind of cover you have, but a Kindle needs one-----it has a glass screen, that can and will break when pressured or fallen. Why spend over 100 dollars for an ereader and not a few bucks for a good protection?
It doesn't have to be expensive, but must offer good protection. My cover has some rigid plastic sheets in it for extra protection, as well as soft wool to protect the screen.
Go and look on the webside of the makers of covers and just try to copy some covers in your own home-made style and design, but with the same idea of protection. You can
make your own or look what kind of money you have to spare
or just order one.
Or if you saved long and hard (as I did) or had a birthday recently (as I had), well....

But take care of that Kindle and screen; it's worth it.