Power BI is collection of software services, apps, and connectors which work cohesively to transform data from myriad resources into business intelligence.
Power BI started its journey as a collection of disparate tools such as Power Query, Power Pivot and Power BI, which were available as plugin in earlier excel version, and now have been integrated in Excel in its Pro Plus subscription services.
Is this service really free ?
Power BI desktop is a complete free tool, available to be downloaded from microsoft website. It may be one of the best kept secrets ever, that such a tool is provided free of charge by Microsoft.
Go ahead, download from Microsoft Power BI and explore