Leaked screenshots suggest RadioShack is planning to launch its own cellphone service. It appears it will share connectivity with Cricket Wireless, which in turn uses some Sprint services.

The RadioShack deal will be without a contract, meaning customers will get little if any subsidy on handset prices. Customers will have a monthly rate for service but no commitment; if their account doesn’t have sufficient credit at the start of the month, service is put on hold unless and until they top up the account.

The screenshots don’t give any details of pricing, though they do show that the HTC One V will be among the available handsets. It’s available elsewhere without contract for around $200-225.

Engadget, which received the screenshots, noted that as well as activating a handset in store, customers can call a phone number that’s already in use by Cricket Wireless. That’s one of the main networks outside of the big four: it currently has around seven million users. Cricket has its own nationwide network, though it leases space from Sprint for 3G services and will eventually offer 4G LTE via Clearwire.

That strongly suggests that RadioShack will be a mobile virtual network operator: one that pays a flat rate (with a bulk discount) to use a “real” network and then resells this access to consumers at a profit. Usually such firms succeed either on the basis of their brand name, or by offering specific packages that suit customers who can’t find a better deal from the major networks.

This can often involve targeting “niche” markets such as people who want a smartphone but won’t make many calls. For example, Cricket Wireless offers special plans for music lovers where song and ringtone downloads don’t count towards data limits. MVNO firms can also try to compete on customer service.

It appears RadioShack will offer many of the same handsets as Cricket Wireless, which most notably has included the iPhone 4 and 4S on contract free deals since June.