Tata docomo is giving best offers than others company, I m using tata docomo science 2010, there is some network problem, all my friends are saying that change the company but I love tata docomo so me and my father were using tata docomo and we had gone a luck sim numbers so we can easy to remember it.so for cheapest network I recomemded these network, if you have not any problems with network.i had buy tata docomo sim at 0rs and I had got talktime of rs30 ans local+std calling at 20ps . so I love to use tata docomo.