We study the private market response to the National School Lunch Program, documenting economically meaningful spillovers to non-recipients. We focus on the Community Eligibility Provision (CEP), an expansion of the lunch program under the 2010 Healthy, Hunger-Free Kids Act. Under the CEP, participating schools offer free lunch to all students. We leverage both the staggered roll-out and eligibility criterion for the CEP, which is limited to schools where at least 40% of students participate in other means-tested welfare programs. We find that local adoption of the CEP causes households with children to reduce their grocery purchases, leading to a 10% decline in grocery sales at large retail chains. Retailers respond with chain-level price adjustments: chains with the most exposure lower prices by 2.5% across all outlets in the years following adoption, so that the program's welfare benefits propagate spatially. Using a stylized model of grocery demand, we estimate that, by 2016, the indirect benefit had reduced grocery costs for the median household by approximately 4.5%.