T-Mobile USA also announced an agreement to sell the iPhone, becoming the last big carrier to sign on with Apple Inc, which will also help it win new customers and keep existing subscribers.

U.S. operators typically pay phone subsidies, giving subscribers discounts in exchange for tying them into a two-year contract. While this helps retain customers, it also ramps up costs, particularly for the higher-priced iPhone.

The No. 4 mobile service provider, which has been struggling with customer losses, already gives customers the option to pay less for their phone service if they forego a smartphone subsidy.

Next year, T-Mobile USA plans do away with subsidies entirely, Chief Executive John Legere said in parent company Deutsche Telekom’s investor meeting, which was webcast.

The move will cut T-Mobile USA’s upfront costs but Legere also expects it to appeal to customers, who dislike restrictions on how often they can upgrade their phones under the subsidy model favored by bigger rivals Verizon Wireless Inc, AT&T Inc and Sprint Nextel Corp.

“We think there is huge room for a challenger to change some of that, in a way that the larger players will not be able to or will choose not to respond to,” the executive said.

Under the unsubsidized model, Legere said customers will be able to upgrade their phones when they want to by trading in the device. T-Mobile USA’s bigger rivals have been restricting upgrades to keep their subsidy costs under control.

He did not say when exactly in 2013 the company plans to switch entirely away from subsidizing phones. Around 80 percent of the company’s new phone activations are currently from subscribers who have decided not to pay a subsidy for their device.