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 primary 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' attendance 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. (Contains 8 tables.)