Abstract: A customer incentive system involving a plurality of service or merchandise providers comprises a customer-carried, portable device (74), a provider device (76), and a base device (72). To earn incentive credits, the customer enters into a transaction with one of the providers participating in the incentive system (70). A transaction amount is derived from the transaction and, based on this amount, an incentive credit amount is computed. The base device (72) performs this computation by deriving an incentive code and cross-referencing this incentive code with all customer incentive codes stored on the customer-carried device (74) and incentive program codes stored on the provider device (76) to derive an incentive rate. This incentive rate is applied to the transaction amount to derive the incentive amount. The incentive amount is stored on the customer-carried device (74).