School food authorities (SFAs) run meal service programs in each school district and are reimbursed at a national rate for meals served to eligible students participating in the National School Lunch Program (NSLP). Previous research (Ollinger et al., 2011) showed that meal costs were lower for SFAs that serve more meals, and Newman, Ralston, and Clauson (2008) found that some large volume buyers reduce their food costs by negotiating price discounts. This paper builds on that research by examining factors affecting purchase costs. The main findings are that cost dropped with the volume of product purchased and with the number of meals served for most foods and varied across regions. A major surprise was that small and middle size SFAs in buying cooperatives and SFAs using school food management companies had higher costs than did other SFAs not using co-operatives or food management companies.