Applications in the area of IoT and smart cities rely heavily on data to manage and control their operational environments. In such applications, machine learning and artificial intelligence algorithms help the government officials, city administrators, and industries to make an informed decision on managing their cities and factories using the data collected from various sources. As we step into the era where ”data is termed as new oil”, there is a need for protocols with support for selling and buying data without giving up the data ownership to third-parties. In this demo, we present Streaming Data Payment Protocol (SDPP), which is an application layer protocol for selling and buying data. SDPP uses blockchain and distributed ledger technology for micropayments and immutable storage of transaction records. In addition, our protocol has a built-in mechanism to set data granularity since the bulk transfer of data between a seller and a buyer may lead to a loss for the seller if the buyer terminates the connection after receiving the data without making a payment. In this demo, we present SDPP and explain how it can contribute to the emerging data economy using a proof-of-concept implementation that uses TCP protocol for data communication and IOTA as both cryptocurrency and a distributed ledger.