When you pay the full price for an unsubsidized phone, carriers will typically knock about $10 off the monthly wireless service plan. But the total cost of an iPhone ($650 for a 16 GB version) more than offsets the savings. The average monthly cost of a no-subsidy plan with zero down is $28 more than if you pay $200 up front. Over the course of a year, that unsubsidized plan will set you back about $75 more than the old-fashioned two-year contract plan, according to estimates from Macquarie Securities analyst Kevin Smithen.