A method for providing on-line payment services is provided where a payment service provider pays for a plurality of purchases that are made by a user during a plurality of on-line shopping sessions. An authorization is received for the payment service provider to collect a reimbursement amount from a financial institution of the user. The reimbursement amount is at least equal to a cumulative amount of the payments for the plurality of purchases made by the user during the plurality of on-line shopping sessions. The payment service provider collects the reimbursement amount in a single transaction from the financial institution of the user and pays a fee to the financial institution of the user. The fee is based on the single transaction carried out to collect the reimbursement amount rather than being applied to each of the plurality of purchases or assessed as a percentage of the reimbursement amount, which allows the payment service provider to reduce the costs associated with providing payment services.