I am currently using an Airtel mobile connection, and by the end of the month I notice that I have made a recharge of around Rs700, I do make calls, but they are for a very short duration. I would like a mobile connection which wouldn't cost me as much for calls, I make local and national calls but mostly local calls. The only thing I use the internet on my phone for is WhatApp, and in case you are thinking I download any videos or images sent to me, I do that at home from my WiFi connection. As I will be heading on holiday soon, I also need a connection which doesn't charge as much for roaming as well.
The best Tariff you can get for your money is from Reliance CDMA( not GSM). They have very good coverage and they are the most affordable in most places I have visited . Also, you can get a Reliance CDMA Postpaid with fully unlimited Local Calls at just Rs. 300 a month plus a 1GB Data. Good Luck.