Micropayments are electronic payments of small amount. Given their low value, the cost of the corresponding electronic transactions should also be kept low. Current micropayment schemes allow a regular amount of money withdrawn from a bank to be split into fixedvalue coupons, each of which is used for one micropayment. A more flexible mechanism is proposed in this paper, whereby coupons of variable value can be generated by a spending program without increasing the transaction cost. Moreover, the spending program allows one of several alternative ways of splitting the amount withdrawn into re-usable coupons to be selected in real-time.