Making purchase decisions

Apparatus and method for use in making a purchase decision regarding purchase of a plurality of units of a good or service from a plurality of potential suppliers (14) at one or more purchasing times, the apparatus being arranged to determine, estimate or otherwise obtain one or more outcomes for each purchasing time based on one or more quantities of units (16) of the good or service potentially or actually required to be purchased at the purchasing time and/or predicted fluctuations of price of said good or service during said purchase period and access details (10) of terms under which said good or service may be purchased from each of the potential suppliers (14). The apparatus is arranged to determine an optimal purchase strategy regarding purchase of the good or service during the purchase period, which optimal purchase strategy is defined in terms of, for each outcome at the or each purchasing time, an allocation among the plurality of potential suppliers (14) of a quantity (16) actually or expected to be required to be purchased so as to minimise a total predicted cost of purchasing the good or service during the purchase period.