(Business 2.0) – These days, companies from EarthLink to 7-Eleven all want to offer their own cell-phone services. But building one, on the networks of major carriers like Sprint, can cost as much as $300 million. Brands that target hard-to-reach demographics, such as Latinos (TracFone) and Gen Y (Virgin Mobile), have been the most successful. So teen-focused Amp'd Mobile, which launches this month, may have a chance. It's the brainchild of Peter Adderton, who founded the hit youth-oriented Boost Mobile. Amp'd will be the first private-label service to offer video and music downloads over a 3G network and the only one working with Verizon, giving it the instant advantage of the nation's largest wireless network.