For $15 a month, Sprint offers unlimited Internet access on a Sprint phone/PDA.  For another $25 a month, you can tether the phone/PDA to a computer and use it as a broadband modem, with unlimited data.  Without an appropriate data plan, Sprint normally charges 3 cents per kilobyte.

I figure that if I didn't have the unlimited tethering plan, my next phone bill would be in excess of $100,000!