Cardboard and Gorilla Glue! I made it because the Otterbox case didn't protect the screen in my pocket. Fits like a glove. The extra cutouts are there for the camera and the power keys.

I wouldn't have a cardboard wallet, because wallets need to be structural, somewhat, but a cardboard case protects like it's nobody's business and was surprisingly easy to make. I'm going all cardboard for electronics from now on.