The prototype model developed in this paper is a deterministic simulation system, used to develop alternative commodity purchase plans and to show their differential impacts in terms of costs, tradeoffs, and benefits. The mod!!1 incorporates systems of demand parameters to account for economic interdependence among commodities, alternative decision criteria to reflect different emphasis on program objectives, and various constraints to account for program operating restrictions and rcquirements. Thc operation of the model is illustrated by a hypothetical example based on Section 32 purchases for the School Lunch Program. The empirical results are reasonably realistic and provide ample evidence to demonstrate the model's usefulness and versatility.