Hey funkybone!
Have you tried using WIFI on your device? This means that you will not be using your data connection, so it won't cost you anything... it does rely on you having an available WIFI network though.
If you mean you want to get a free 3g connection, I do not think that is possible - we would not condone discussion of anything that could be considered as fraud (i.e. not paying your network carrier for data usage on their network).
Hope this is of some help!