Tata DoCoMo is running a special scheme under which you can get 1GB 3G data for around Rs. 31.
This offer is slightly complicated. You have to recharge your connection for Rs. 246 which gives you 219 rupees of talk time.
And then you have the ability to recharge for an addition 4 rupees which gets you 1GB data for use within a period of 30 days.
So, overall you are getting 1GB data for Rs. 31!