Taxable Supply or Exempt supply

GST will be charged on the ‘transaction value’. Transaction value is the price actually paid (or payable) for the supply of goods/services between un-related parties (i.e., price is the sole consideration)

you can have more details from the following kink:

https://www.cbec.gov.in/resources//htdocs-cbec/gst/eflier-meaning-scopeofsupply14062017.pdf