The carrier will also offer up to $350 per line to T-Mo subscribers to cover costs related to switching networks.
An earlier version of this story did not account for the fact that T-Mobile is waiving the $99 down payment on iPhones when people trade in their old devices. With this factored into the overall savings of the trade-in, T-Mobile's trade-in program actually offers consumers a better value than other trade-in sites such as Nextworth.
But there's a catch: You have to commit to a new smartphone as part of the new upgrade program. Also, only a select number of flagship phones are available for an upgrade.
The carrier's new "Never Settle" promotion will give Verizon customers a free phone to play with for 14 days and then pay Verizon's early termination fee for customers who switch over permanently.
CNET's Marguerite Reardon takes a look at T-Mobile's new plan to entice wireless customers to jump ship from their existing carriers.
The carrier is also guaranteeing that prices won't increase for customers on existing plans -- even if you're on a promotional program.
Customers can trade in their existing iPhones (or other smartphones) for a better monthly rate.
As part of its settlement with the Federal Trade Commission, T-Mobile will pay at least $90 million in customer refunds, as well as penalties and fines over complaints that it put bogus charges on customer bills.
Can't afford the steep off-contract prices for Apple's new smartphones? T-Mobile joins other wireless carriers in aiming to make it easier for users to pay them off.
After the Federal Trade Commission filed a complaint against T-Mobile this week, CEO John Legere derided the agency's claims.