Apache Druid
7.2#2 in streaming analytics softwareFree planFree planWebAPILinuxmacOS
VisitNo prices published.
Druid suits teams building user-facing analytics or working with streaming data that need low-latency, concurrent queries and quick visibility into incoming data. It can also serve ad hoc analysis of semi-structured data such as JSON.
You want what its maker publishes above — check its page for the details.