Many crypto-currencies, Bitcoin being the most prominent, are reliable electronic payment systems that operate without a central, trusted authority. They are enabled by blockchain technology, which deploys cryptographic tools and game theoretic incentives to create a two-sided platform. Profit maximizing computer servers called miners provide the infrastructure of the system. Its users can send payments anonymously and securely. Absent a central authority to control the system, the paper seeks to understand the operation of the system: How does the system raise revenue to pay for its infrastructure? How are usage fees determined? How much infrastructure is deployed?

A simplified economic model that captures the system’s properties answers these questions. Transaction fees and infrastructure level are determined in an equilibrium of a congestion queueing game derived from the system’s limited throughput. The system eliminates dead-weight loss from monopoly, but introduces other inefficiencies and requires congestion to raise revenue and fund infrastructure. We explore the future potential of such systems and provide design suggestions.