In this paper, we propose a new local economic infrastructure—“community cash”—based on blockchain and activity-based micro-pricing technologies. Blockchain technology, introduced by Satoshi Nakamoto in Bitcoin: A Peer-to-Peer Electronic Cash System  in 2009, has had a serious impact on the virtual economy. It has realized peer-to-peer digital data transfer without the trust of third parties. On the other hand, activity-based micro-pricing alters user behavior through economic incentives. By combining these technologies, we develop a blockchain that runs on a new consensus algorithm, proof-of-contribution. This consensus algorithm alters the behaviors of the members in a community by distributing rewards for generating blocks as monetary incentives. We first introduce the system of “community cash,” and then discuss future works that can be implemented in the proposed infrastructure as well as remaining problems to be solved.