How to jailbreak my iPhone 4S to have data plan without paying for it?

My brother told me you can but I wasn't so sure. I don't know much about jail breaking and If there's a way can you please tell me how to do it.

No, because the carrier (AT&T, Verizon) control that from their system and if it's not turned on by them then there isn't another way to turn it on.

No.Unless you set up your own server which would cost thousands of dollars.