So lets start with the full form of GST , GST is Goods and Service Tax. But it is a bit different from the taxes that we had till now. So here I will be trying to make it as simple as possible.
So, Imagine that you are a student and today is your birthday. And you bought some chocolates to your give it your friends. And in the morning your saw your friend Raju and his mother and gave them chocolates.And on the way to school you saw the gate keeper in front of the school gate so you gave one chocolate to him also. And then you reached the class and gave chocolates to all the students in the class room. And now your friend Raju gets 1 more chocolate and in total he gets 2 chocolates .But your friend Arun was absent on that day , so he did not get any chocolate .
Now , consider your Birthday as your Business , Chocolate as your tax. So the chocolate that you gave to your friend Raju and his mother is the " Local Tax ". And the chocolate that you gave to the Gate Keeper is the " Entry Tax " . And the chocolates that you gave to your classmates is the " Service Tax ". And your friend Raju got the chocolates twice and that is " Surcharge ". But your friend Arun did not get any chocolates. So the principal of the school created a new rule that the Birthday boy should give all the chocolates at office and the principle will give it to all. So Raju will get the chocolates only once but Arun will get the chocolate too. This is GTS ( Or in Modi's Words - Good Simple Tax ).