Abstract: Customers provide payday and creditor/biller information to a payment service, which determines the customer's aggregated monthly payments on periodic accounts such as vehicle loans and mortgages and then on each payday deducts a fraction of the aggregated amount in a single transaction, resulting in only a single fee to the customer. The fraction depends on how many times per month the customer is paid. The customer's funds are held in a trust account and on days that payment for a respective creditor is due during the month, the respective creditor is automatically paid out of the trust account.