"Warren Buffett's 24-year-old wallet was recently purchased for $210,000 at a charity auction because it included a stock tip. But before Buffett sent his wallet to the winning bidder, he removed a significant and personal item that reveals 10 secrets to his extraordinary wealth-building success."
I just came across this info yesterday. You can read about it here. This should be a great addition to Flatwallet's wallet since there is a lot of room.