Ever find yourself needing a phone stand in the restaurant, in the office or at your favorite coffee shop? I have and many times I'd prop my phone up against my drink to watch something, or to keep the kids entertained while waiting for food or the check.
This fits inside your wallet and cost next to nothing in time and filament to print. This will eventually break at the folds due to the nature of the material used. But print a few extras for yourself, your friends, and co-workers.

Print instructions

Multi-material printing would be absolute best for this. Where the main body can be any rigid filament and the hinges can be flexible filament.