I had the idea to make a phone case that also functioned as a wallet. Turns out this product already exists in the Incipio Stowaway. For only $15-$18 (depending on the color), you can get an elegant phone case that looks just like a normal case, but also has room for 3 credit cards AND a bill. This essentially means you no longer have to carry around a wallet! I highly recommend the Incipio Stowaway.
See a video of how easy it is to use the Stowaway:
By Brian Roizen