In this paper we analyze a supply contract for a single product that s
pecifies that the cumulative orders placed by a buyer, over a finite h
orizon, be at least as large as a (contracted upon) given quantity. We
assume that the demand for the product is uncertain, and the buyer pl
aces orders periodically. We derive the optimal purchase policy for th
e buyer for a given total minimum quantity commitment and a discounted
price. We show that the policy is characterized by the order-up-to le
vels of the corresponding finite horizon and a single-period standard
newsboy problem with no commitment but with discounted price. We show
that this policy can be computed easily. We can use this to evaluate a
ny discount schedule characterized by a set of (price discount, minimu
m commitment) pairs.