A method of arranging for payment of a purchase includes receiving, from a supplier, agreement to accept a payment from a buyer via use of a payment card having variable payment terms; after a purchase by the buyer from the supplier, assessing the supplier a standard interchange rate; receiving, from the buyer, approval to pay the invoice; and issuing, to the supplier, a rebate, based upon when the approval to pay the invoice was received. the variable payment terms are calculated by: determining a first early payment date; determining a second standard payment date; assessing against the supplier a first percentage of the standard interchange rate if the invoice is approved by the first early payment date; and assessing against the supplier a second percentage of the standard interchange rate if the invoice is approved on or after the second standard payment date.