The last city I knew to be quite cheap is Mumbai. Not actually sure since I had never been in there, but a few of my friends who had been there say so.
I have experience of many places. I have lived in Bhubneshwar, Kolkata, Mumbai, Patna, Ranchi, Bhagalpur, Cuttak, Vishakhapatnam and now Delhi. As compare according facilities Vishakhapatnam is the cheapest city.