Sprint is getting rid of two-year smartphone contracts, following a move made previously by T-Mobile US and Verizon Wireless.

"By the end of the year, customers of the No. 4 wireless company will have to pay the full price for their phones or spread the payments out by leasing the device, an option that started last year," CNBC reported.

Sprint CEO Marcelo Claure explained the move in an interview with CNBC. Buying a new phone at the subsidized rate of $199 is "a thing of the past, the industry has changed," he said.

Yesterday, Sprint announced that customers can lease a 16GB iPhone 6 for $22 a month and upgrade to the next version of the device as long as they continue paying that $22. That's in addition to the monthly fee for mobile data, calling, and texting.

"Every single time there's a new iPhone you just go to the store, drop off your old iPhone and pick up a new one and that's included in your rate plan of $22 a month," he said.

This is different from Verizon's model, which requires customers to pay off the full cost of a phone before getting a new one.

$22 a month adds up to $65 more than the standard subsidized rate of $199 over the course of a year. But Claure noted that in exchange for a subsidized phone, customers "used to pay a much higher monthly fee" for data, calling, and texting. (Those pesky subsidies and contracts also require customers to pay early termination fees in order to switch carriers.)

"We've done a lot of research, we've talked to a lot of customers, and what they've told us is that probably one of the most frustrating things in this industry is the fact that new technology gets released every year... however, customers sign a two-year contract," Claure said.

Sprint offers different upgrade paths for Android phones. Last week, it announced lease pricing starting at $25 a month for Samsung's new Galaxy phones, with the ability to upgrade after 12 months. Customers can also buy those phones with two-year contracts at subsidized rates starting at $249.99, since Sprint's plan to eliminate contracts hasn't taken effect yet.

When asked why Sprint is able to offer new iPhones and upgrades for just $22 a month, Claure explained that the company is working with a partner to resell year-old iPhones. "There's a huge market for customers who cannot afford to buy a new iPhone but would love to get their hands on a device that is less than a year old," he said. The re-sale initiative is with Brightstar, which like Sprint is owned by SoftBank.

The only major nationwide carrier that hasn't said it will eliminate contracts is AT&T. But while AT&T still offers two-year contracts in its stores and online, the company's marketing prioritizes device payment plans. In third-party retail stores that sell AT&T devices, customers can only buy them for full price or with installment plans.