Mobile Internet can never be free. Face it. All those methods on the web are a waste of time, and will never work, unless you are an expert hacker.
Here it is! [P.S: Work only for Airtel Prepaid]
1] In the home screen/standby mode, type *567*1# and call.
2] In the message you get, you will be informed about the activation of Mobile Office, which charges you 30 paise/50KB, rather than the regular 30 paise/20KB.
3] Hit OK, or Answer, or whatever, and reply 1 in the Service Command Editor.
4] You’ll be notified that Mobile Office will be activated in the next 1 hour, but it hardly takes a minute, when you wil receive the settings. Save them, and make them the default ones.
5] Download Opera Mini, and run it with Mobile Office. It works wonders. Awesome speed, cheap internet!