A year and a half ago, my favorite handbag bit the dust. Not being able to find something similar, I decided to make my own. I made a passport-sized prototype, at which point a friend suggested making RFID-shielding passport wallets. I researched, found an excellent copper mesh fabric made for data-shielding purposes, and a week later, Faraday Bags was born.
When one of my customers said that she decided she needed a Faraday wallet after reading "Little Brother," I decided to check it out. Imagine my surprise to find that the MC uses a similar device, also called a Faraday Pouch!
At any rate, I make RFID-shielding passport pouches in a variety of designs ranging from $15-$30. The patented copper mesh I use blocks RFID transmission between 10MHz and 20GHz (most "smart cards" transmit at 13MHz.)
My bags come in several fabrics or designs, but I'm very happy to consider custom work.