Gift Certificates
L's school sells gift certificates for a huge number of places. Each company gives a percentage to the school. Most give between 1% and 5%, and with those profits: the school bought $4000 worth of new textbooks. And there's a little family owned restaurant in South City named "Crusoe's". Their food is fabulous, plentiful and cheap. Their bar, dining rooms and outdoor areas are spotlessly clean. And they donate 20% of their gift certificate sales to L's school. (And, presumably, any other schools who sell their gift certificates)
Twenty Percent! And their food is fabulous!

You gotta love the small business owner.