Google has added isAccessibleForFree to the datasets structured data help document. This new property tells Google Search if the dataset is accessible for free or if you need to pay to access the data.
Dataset structured data helps Google understand your datasets on your website and makes it easier for Google to find when you provide supporting information. This includes information such as name, description, creator and distribution formats as structured data. Google's approach to dataset discovery makes use of schema.org and other metadata standards that can be added to pages that describe datasets. The purpose of this markup is to improve discovery of datasets from fields such as life sciences, social sciences, machine learning, civic and government data, and more. You can find datasets by using the Dataset Search tool, Google said.
Here is a snippet of how this property might look like in your code:
Forum discussion at Twitter.
