Virgin Mobile prepaid cards are sold at a 7-Eleven store in Los Angeles on Thursday, June 7, 2012. Virgin Mobile, one of Sprint's brands for prepaid, no-contract phone service, says it will start selling the iPhone on June 29. The phone will cost for $549 for a basic model but service will be cheaper than usual, at $30 per month. The iPhone has until recently been restricted to contract-based plans. Now, the floodgates appear open for the phone to enter the prepaid, no-contract market, which is aimed at people with low incomes and poor credit.