Netdata doesn't have any paid service at the moment, event the Cloud service is free.
There are plans in the future for some paid plan but it won't remove features, it is more on having longer retention on metadata, role based access, support, etc.
As far as I'm aware it is actually free for both agent and cloud. What do they have now is more than enough to understand the root of the issue.
It is ok to pay in the future for SSO.
My concern is not money at that moment, but the foot print on production system as data will be stored and queried next to prod with recently introduced anomaly advisor on top.
There is no central storage of data, data are stored on each monitored system in a database called dbengine, that's all. Cool, right? They do have a data privacy page: https://learn.netdata.cloud/docs/cloud/data-privacy
There is nothing paid, everything is free, both the agent and the cloud app. Do whatever you like with it. There is a pricing policy that will follow sometime in the future but everything that is free today seems that will remain free forever.
There are plans in the future for some paid plan but it won't remove features, it is more on having longer retention on metadata, role based access, support, etc.
You can find more details here https://www.netdata.cloud/pricing/