Home internet is $45.00 / month and my plan on an old iPhone is only $15.00/month - no data. iPhone 3G doesn't have tethering. Thinking of ditching ISP and for the same monthly $ total buy a new iPhone 5c and just tether my macbook to it since I'd be getting an unlimited data plan. I'm assuming many people have gone this route? How can you go wrong IF your data plan is unlimited?