But most of the students aren't able to use this app because most them don't have (supported)credit/debit card.
Most banks provides Rupay card which is not accepted in Google Play.
And the most silly part is this that even for free book you need to enter the payment details, because they aren't free , they costs ₹ 0.
But with a simple trick you can bypass this hurdle.
Google requires you to just add payment details.When you add Credit/Debit card details Google can easily verify the authenticity of those details but not in case of NetBanking.
So just add any bank as your netbanking service and then you will be able to purchase ₹0 books.
Here is a video guide for doing this. Hope this helps.