YaOweMe

Free. No ads. YaOweMe doesn't just keep track of money you owe others and money others owe you, YaOweMe facilitates agreement of a debt. Each participant must agree to the debt and does so through the app, signifying this with a digital signature. The messages are sent peer-to-peer, they are not stored on yaoweme.com.
That's what you get with this app. No eye-catching graphics or cute sounds. Just solid functionality that encompasses all phases of a debt between two people. Since agreement is required on both ends, I wrote two different versions of this app to cover most smartphone users.
YaOweMe has nothing to do with digital currency. YaOweMe does not facilitate any actual payment. YaOweMe just provides the messaging and tracking.
YaOweMe transfers messages via a variety of wireless media, depending on what is available.
yaoweme.com does not store or backup your information. It will only store your randomly generated ID and public key to ensure that the digital ID cannot be reused by someone else.