Phone case with emergency card compartment

Phone case with a spot to store an emergency credit card and a $20 bill. How to create a compartment in any dual layer phone case to hide an emergency credit card and an emergency $20 bill, this is an easy diy project, just trace the outline of a credit card on the rubber inner layer, cut it out as precisely as possible with a sharp x-acto blade. Fold your $20 bill over 3 times, place it against the phone then put the credit card over it, put the outer layer back on, now you are ready for emergencies, or just to make yourself feel better about always having some way to pay. Until everyone takes Apple Pay and android pay!!!