While a retail price of Rs 40 (50 cents) is possible it is not the norm and is considered expensive even in a big city like bangalore.

The price flucatates and does drop below Rs 10 and even Rs 5 . Here the coconut board link [1] for wholesale prices.

I have personally traded with farms at Rs 5-6 range 3 years back in 2016.

[1] https://coconutboard.in/priceweb/Reports.aspx

Today I can see vendors quoting 10 per on some mundis.