Clarifying free edition limitations

1. There are many cloud-based data sources such as CRM Online, SharePoint Online, etc. that the free version allows you to refresh Daily. However, no on-premises datasources, you need the Personal Gateway for that and that comes with Pro

2. Streaming data comes from things like Azure Streaming Service, basically IoT type data

3. Certain data sources, such as SSAS are considered "live" data feeds meaning that refresh is not required to get the latest data.

https://support.powerbi.com/knowledgebase/articles/665278-analysis-services-tabular-data-in-power-bi-desktop

 From:

https://support.powerbi.com/knowledgebase/articles/664495-free-trial-for-power-bi-pro

• Connect to on-premises data using Personal Gateway
• Enable live interactive connectivity to the following sources:

• SQL Server Analysis Services
• Spark on Azure HDInsight
• Azure SQL Data Warehouse
• Azure SQL Database