This paper adds a measure of school costs to the model of determinants of schooling. Costs are estimated with controls for selection into school and the possibility of receiving free pri- mary education (FPE). Controlling for costs, household wealth has a large, positive effect on primary school attendance with greater income elasticity for girls than boys. Girls’ atten- dance also depends on opportunity costs generated by providing child care for younger siblings and living on a family farm. Policies that increase household resources and reduce opportunity costs are recommended to complement free primary education.