Generic queries on Power BI

PowerBI free and Pro users have a maximum 10 GB data storage but Pro users can create app workspaces, with a maximum 10 GB data storage each. 

So a Pro user can have 10 app workspaces to give 100Gb storage but spread across 10 GB chunks. There is no mention of a limit I have seen for app workspaces.  Additional storage can't be bought from what I have seen. Power BI Premium comes with 100 TB of storage! 

https://docs.microsoft.com/en-us/power-bi/service-admin-manage-your-data-storage-in-power-bi

Also worth pointing out the differences between Power BI Free vs Pro, as this changed not so long ago:

What capabilities are being added to the free service?

Beginning June 1, 2017, the free service will have capabilities equivalent to Power BI Pro, except for sharing, enterprise distribution, and collaboration. This includes the same 10 GB workspace limit, up to 8 daily scheduled refreshes for datasets, and maximum 1M/hour streaming data rate. We’re also including access to all data sources, including those available through the on-premises data gateway

Which Power BI Pro capabilities are not available with the free service?

Peer-to-peer dashboard sharing, app workspaces (previously referred to as group workspaces), Analyze in Excel and Power BI Apps (unless backed by Premium capacity) are capabilities limited to Power BI Pro.

Power BI Pro is included in Office 365 E5. Power BI Desktop can be used for free as well as by Pro users - https://docs.microsoft.com/en-us/power-bi/service-frequently-asked-questions.

That's as much as I was able to find anyway!