Measuring the price of data in commercial data marketplaces.

A large number of Data Marketplaces (DMs) have appeared in the last few years to help owners monetise their data, and data buyers optimize their marketing campaigns, train their ML models, and facilitate other data-driven decision processes. In this paper, we present a first of its kind measurement study of the growing DM ecosystem, shedding light on several totally unknown facts about it. We show that data products listed in commercial DMs may cost from few to hundreds of thousands of US dollars. We analyse the prices of different categories of data and the challenges of comparing across DMs. We also analise the pricing of specific sellers and products to identify features that apparently correlate with prices, and we point to the need and the challenges of building a quotation tool for data products based on market data.