The latest installment of the Fordham Institute's "Creating Sound Policy for Digital Learning" series investigates one of the more controversial aspects of digital learning: How much does it cost? In this paper, the Parthenon Group uses interviews with more than fifty vendors and online-schooling experts to estimate today's average per-pupil cost for a variety of schooling models, traditional and online, and presents a nuanced analysis of the important variance in cost between different school designs. These ranges--from $5,100 to $7,700 for full-time virtual schools, and $7,600 to $10,200 for the blended version--highlight both the potential for low-cost online schooling and the need for better data on costs and outcomes in order for policymakers to reach confident conclusions related to the productivity and efficiency of these promising new models. (Contains 2 figures and 4 endnotes.)