T-Mobile, the only of the four major carriers not to offer the iPhone, has finally joined the club. At a media event today in New York City, the company announced it will begin selling the iPhone April 12 — but with a difference. Unlike the other carriers, which sell the iPhone for a subsidized price of $199 if one signs a two-year contract, T-Mobile is switching to only selling unsubsidized, contract-free phones. You make a $99.99 downpayment, and then pay $20 per month for two years to pay for your phone. That works out to a total cost of $580.