Leap Wireless, the company that owns Cricket, announced that it will be the first carrier to offer prepaid iPhones in the U.S. on a no-contract basis.

The service will begin June 22, with the iPhone 4S starting at $500 and iPhone 4 at $400. Service cost will begin at $55 per month for unlimited calls, texting, and data.

Cricket has always focused on selling no-contract, prepaid services to low-income households. Because its own network is limited compared to bigger carriers, it depends on Sprint’s network for areas where it is lacking. The iPhone is compatible with only a part of Leap’s service, including Houston, Austin, Portland, Pittsburgh, and Salt Lake City.

Though Leap says the plans are unlimited, the company does have a cap on its usage, slowing down data after 2.3GB, which is slightly lower than Verizon or AT&T.

The iPhones are extremely popular, but its steep price has stood in the way of sales. Since Leap concentrates on low-income customers, the company knows it’s taking a chance by buying the phones. In fact, Leap doesn’t expect more than 10% of its customers to buy the iPhones, even though the company’s prices are relatively low compared to what other carriers charge.

Verizon Wireless, AT&T and Sprint all sell the iPhone, as do other smaller phone companies.