It is most cheapest operator than any other in India
Some operators gives calling cost cheap and some gives Internet cost cheap and some operators have both high but network signal awesome but this is not with Tata Docomo
It has cheapest calling packs as well as net packs and the network signal are also decent not best as other operator but considering its cheapest packs it can be negotiable .
I am using Tata Docomo from 4 years this is personal experience over it .
Thank you