Responding to rival T-Mobile's $5 plan, Sprint announced a $1 per month plan for Apple's new iPhone, which launches on Friday. Sprint said on Thursday customers can get a 16 GB iPhone 6s for $1 per month and an iPhone 6s Plus for $5 a month, when trading in an iPhone 6.

Rival T-Mobile US is offering the 16 GB iPhone 6s for $5 per month in exchange for an iPhone 6, 6 Plus or Samsung Electronics Co Ltd's Galaxy Note 5 and Galaxy S6 versions.

However, both Sprint's and T-Mobile's plans require you to trade in an iPhone 6, which essentially amounts to a $300 (or more) down payment. Your phone will be resold in the secondary market instead of you just doing that yourself.

Apple is also offering its own financing scheme for an unlocked iPhone, which gives a customer the liberty to switch between carriers, rather than be tied down by a contract with one carrier.