An off-line economy for digital media. In one implementation, exemplary media devices of buyer and seller participate in the off-line economy by performing secure off-line transfers of digital media content between themselves. The media devices store proof of the off-line sales transactions, so that a percentage of the sale price can be applied to a copyright owner and a percentage of the sale price can be applied to the seller as an incentive. Even resale of pirated media content benefits the copyright holder. The off-line economy opens an effective and inexpensive distribution channel for copyright holders and allows buyers to obtain media content anywhere, at any time, from any participant in the off-line economy without connecting to the Internet. The off-line economy allows copyright holders and media sellers to optimize pricing by market probing.