A postage funds credit system in which the customer pays for postage funds after they are used in franking mailpieces. A postal device is initialized with postage funds advanced to the customer by a third party. The value of a descending register of the postal device is read a first time and a second subsequent time. The later value is subtracted from the earlier value to obtain an amount of postage funds used by the customer between the two readings. The customer is billed for the amount of postage used after such use. The postal device can be replenished with additional postage funds advanced by the third party.