NEW YORK » Leap Wireless, the parent of the Cricket cellphone service, says it will be the first mainland U.S. phone company to sell the iPhone on a prepaid, no-contract basis.

Starting June 22, Leap will start selling the iPhone 4S starting at $500 and the iPhone 4 starting at $400. Service will cost $55 per month for unlimited calls, texting and data.

Leap Wireless International Inc., which is based in San Diego, focuses on selling no-contract service to low-income households. Its own network is limited to some cities. Elsewhere, it uses Sprint’s network.

Larger carriers also sell the iPhone on a no-contract basis. But those phones cost more, and service costs the same as when on-contract.

Open Mobile started selling iPhones on a prepaid, no-contract basis in Puerto Rico on May 18.