Samsung Instinct M800
Without an unlimited plan?
The reason being with a phone like the Instinct, requiring the everything plans actually makes Sprint's life easier. With the PDAs, some idiot will always say they don't want the internet/gps/messaging packages, use the crap out of the pay as you go internet/gps/messaging, wind up with a HUGE bill, and complain to the company because of their stupidity.
In a sense, they've largely idiot-proofed the plan..