While it is free to download it, the license still costs. Though they seem to let you use it unlicensed for an unlimited amount of time with some restrictions (like not being able to change the background image and an ever present watermark). At least this was true for windows 10. No telling if/when they will drop that feature though, especially if loads of people start using it unlicensed like that (though I doubt that has any effect on people using it that way or not).

Only for existing users+machines who are upgrading. New machines gotta pay up.

Was, but no longer is. It is officially discontinued, making the ₹500 note the largest for now. I would expect the Government to quickly launch a new large-denomination note. India is still a largely cash society and the largest note being worth 6 USD is surely going to be inconvenient for everyday citizens.

The Government demonetised ₹1000 and ₹2000 banknotes a few years back as part of a campaign against “black money”. The Government’s thinking was that criminal organisations hoarded large amounts of cash in these large-denomination notes, and by forcing everyone to deposit the notes immediately into the bank, it would bring light to the flow of money.

It was not particularly successful and mostly all it did was lead to a week of chaos and long queues outside banks.