Will Your Wireless Bill Get Cheaper?

T-Mobile gave cellphone users plenty to talk about Monday when it unveiled a cheaper version of its unlimited plan for longtime customers.

People who have used T-Mobile (DT) as their provider for at least 22 months can now talk as much as they want for $50 a month. Combined with a $35 unlimited messaging and data plan, that’s a 15% savings off the regular $100 price. Adding another line to the plan runs just $40 a month. In another bonus, those longtime T-Mobile customers who transfer a line from another carrier to their family plans get a $135 credit they can apply to their bills. T-Mobile confirmed its new loyalty plans, but declined to comment further.

The gambit is just the latest of several new offerings from wireless carriers intended to push down the price of chatting for loyal customers. In February, Sprint (S) launched Sprint Premier, a loyalty program for customers who have a monthly plan valued at $60 or more, a shared plan valued at $90 or more, or who have been Sprint customers for more than 10 years. Members may also upgrade their phones at preferred prices after one year instead of two, receive 25% off accessories and earn free minutes. Not to be outdone, Verizon Wireless (VZ) quickly followed suit, letting customers with monthly plans of $60 and up pick five friends for free unlimited talk, even if those friends aren't on the Verizon network.

Why all this largesse? Thank the slumping economy and brutal competition. Wireless providers know that although cash-strapped consumers are unlikely to cut cellphones entirely out of their tightening budgets, they are taking a hard look at which plans and carriers offer the most bang for the buck. (For tips to cut your bill, click here.)

"They all want to keep customers from looking elsewhere," says Rob Enderle, president of technology advisory firm Enderle Group in San Jose, Calif. After all, given the state of the economy, the loser in this price war could go out of business. “There could stand to be one less provider in the marketplace, and each would rather it not be them.”

Expect the major players to ratchet up the competition in coming months by rolling out added value or discounts to retain current customers, says Michael Gartenberg, vice president of strategy and analysis for Interpret LLC, a market researcher. His pick for the next carrier to make a move? AT&T (T), which could find its advantage as the only carrier to offer rollover minutes diminish as consumers look for more consistent value. AT&T did not respond to requests for comment.

Carriers are likely to drop prices even further on unlimited plans in a bid to gain new customers, says Delly Tamer, CEO of LetsTalk.com, a site that helps consumers compare cellphone plans. Unlimited plans are gaining popularity, and it's easy to see why: They allow consumers to eliminate landlines or consolidate several wireless lines under a single family plan. "Before it was a rich person’s plan," Tamer says. "Now it’s a recession-fighting plan." Indeed, in January, Sprint’s Boost Mobile (which offers prepaid plans with no contract) launched a $50 nationwide unlimited plan that includes talk, text, data and walkie-talkie.

Sprint spokeswoman Emmy Anderson declined to comment on potential offerings, saying the carrier is always evaluating its pricing to offer the best value. Verizon Wireless also declined to comment. "This is a very competitive business," says spokeswoman Brenda Raney. "We don't discuss future plans."