Virtual cellular network operator Helio today said that its subscribers can now use Obopay, a mobile payment system created by MasterCard. The system revolves around a prepaid credit card account that can send or receive money directly from the phone itself without the immediate necessity of the physical card itself. Obopay on Helio's network is effectively a peer-to-peer system, the carrier says: money can be sent to anyone with a cellphone, and the phone owner's contact list can be integrated with Obopay to send or receive money through recognizeable names instead of numbers. Ringtones can be personalized to identify when particular friends or family call in with a payment. Signing up for the Obopay service is currently free; MasterCard says it makes money through the service by charging 10 cents when sending money.