NEW YORK (TheStreet) -- In the latest version of T-Mobile's (TMUS) - Get Report "Uncarrier" campaign, designed to win customers from its rivals, the country's No. 4 carrier says it means business. T-Mobile U.S. CEO John Legere came to New York to announce Uncarrier 9.0. "We're going to do for business what we did for consumers," Legere said.

Uncarrier 9.0 offers businesses a simple pricing plan with discounts of up to 40% over its competition.

"Need 20 lines? 100 lines? 500 lines? That's $15 per line," said Legere. "For every line beyond 1,000 lines, the price is $10. And -- in stark contrast to the other guys -- every line at T-Mobile comes with unlimited talk, text and up to 1 GB of 4G/LTE data. Need more data? Simply choose to add high-speed data per line or add a data pool that all employees can access for phones, tablets and other devices. Or go with a pooled data option that's nothing like the other guys' shared data schemes."

Businesses can also get a free .com domain and Website for wireless users as part of a new deal T-Mobile has signed withGoDaddy. Plus, T-Mobile is offering free email tools from Microsoft (MSFT) - Get Report , as well as what Legere called BFD -- business family discounts offered to corporate users' famiiles.

Legere said that, thanks to the popularity of its Uncarrier programs, T-Mobile nabbed 100% of the growth in the U.S. postpaid cell phone industry last year. T-Mobile shares were up 0.73% to $32.91 in late-afternoon trading in New York.

In its efforts to get people to switch over the past two years, T-Mobile tried Uncarrier schemes offering everything from cut-rate individual and family plans, unlimited data for music streaming, improved 4G connectivity, Wi-Fi calling, international data coverage, no data overage fees, and innovative ways to pay for new handsets. In the wake of each announcement, other carriers were forced to follow suit.

T-Mobile is extending the concept of paying customers' early-termination fees by offering to pay all outstanding device costs (including leases) up to $650 per phone and 10 lines.

Legere also said he's also bringing the contract back in something called the Uncontract: Your rates may go down, but they wont go up. All fixed data promotion plans are now permanent. Unlimited plan customers will get at least two years before their plans expire.

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This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.