works at JAIN KHUSHBOO & CO
172 Points
Joined July 2015
As per sec 15(1) value of supply of goods or services or boyh shall be the transaction value,which is the price actually paid or payable for the said supply of goods where buyer and seller are not related and price is the sole consideration.
In your case GST will be levied on whole amount of Rs 500.
There is no provision in law for valuation on different basis when your input is exempt.