For Boost Mobile, change is in the air. The prepaid division of Sprint Nextel is expanding its target demographic and switching up its rate plans.

Company representatives said the prepaid company’s target audience is shifting from the traditional 14-to-24-year-old crowd, with an emphasis on urban youth and action sports, to one that is more geared to the 18-to-35-year-old market that includes singles as well as families looking for a reliable network and flexible payment options.

In the “what-you-see-is-what-you-get” department, Boost last week launched a new flat rate of 10 cents per minute for all calls, regardless of time of day, for its Pay As You Go Basic Plan. Boost Mobile offers pay by the minute, day and month pricing options. Customers also can get unlimited Nationwide Boost Walkie-Talkie for $1 a day.

The new 10-cent rate is part of how Boost plans to remain relevant in today’s economy, according to Neil Lindsay, Boost’s vice president of marketing and one of its early founders. This week, Boost is making the rounds, visiting with dealers and distributors around the country to outline its new strategies.

Back in the day, Boost was a pioneer in the prepaid space, and it developed a brand to represent a lifestyle. But now it needs to evolve that, both in service offers and what it communicates to the marketplace, Lindsay said.

Consumers still get better per-minute rates with postpaid plans, he admitted, but the gap is closing. Of course, Boost sees prepaid as one of those segments with the potential to survive and grow even in tough economic times, when people might not want to sign or re-sign a 2-year contract with a postpaid plan.

Earlier this year, Boost named Matt Carter, former senior vice president of base management at Sprint, as president. In August, Jeff Auman joined Boost as vice president of sales and distribution; he was vice president of local marketing at Sprint.

Boost expects to add more to its line-up of handsets in the coming months, Lindsay said, as it works with sole handset supplier Motorola. Boost representatives had no comment on what might happen if Motorola were successful in selling its handset business.

Boost also hasn’t said whether it will do anything with WiMAX; Sprint is in the process of merging its WiMAX properties with Clearwire. Boost provides basic voice, text and the walkie-talkie service, as well as navigation and social networking, but it hasn’t been a big pusher of video, which is one of the applications often cited to benefit from WiMAX.

Boost reported 4.2 million subscribers as of the end of June. Its iDEN offering is available nationwide, and its Unlimited by Boost CDMA offering is now available in 19 markets.