A method of preparing a mailpiece includes applying a mailpiece identification (MI) code that uniquely identifies the mailpiece, and applying a destination code to the mailpiece signifying at least part of an address. Tracking and accounting for such a mailpiece includes: at an postal service mail processing (MP) site, obtaining the MI code and the destination code, and sending a mailpiece message including at least the MI code to a postage vendor (PV) site; and at the PV site, storing information from the mailpiece message, debiting an account of the mailer for postage, crediting an account of a postal service for postage, and when the mailpiece message indicates that the mailpiece has arrived at its destination, retiring the MI code as no longer available for use on a mailpiece (at least for some predetermined time).