T-Mobile has kickied off an "unparalleled promotion," offering all devices in its lineup for no upfront cost whatsoever.

In other words, interested T-Mobile customers will be able to get any smartphone, tablet, feature phone or hotspot for $0 down. Of course, the monthly installments remain in place, which means that although users can get a new device for $0 down, they will still pay for said device in the following 24 months.

T-Mobile has been offering a payment system where they charged customers an upfront sum for a device, with subsequent equal monthly payments for 24 months. This helps customers separate their device payments from their actual plan and it makes it more convenient for many to purchase a new gadget. For the carrier, meanwhile, this scheme likely drew more customers to its nest.

"In time for back-to-school, T-Mobile US, Inc. (NYSE: TMUS) will drive an unparalleled promotion this summer, dropping the upfront price of its entire lineup of devices in stores nationwide to zero dollars down," T-Mobile announced in a press release. "With this promotion, new and existing well-qualified consumers and small business customers will get affordable and hassle-free access to the latest 4G LTE smartphones, tablets, mobile hotspots and feature phones at the upfront price of $50 down with monthly device payments."

"The number of reasons not to switch to T-Mobile is ZERO," added John Legere, T-Mobile's president and CEO. "This is a fantastic offer and we're making it easier than ever for customers to get the latest amazing devices. Adding Zero Down in addition to JUMP! and Simple Choice with no contract is all about making wireless work for consumers and shaking up this industry."

On the other hand, there may be a little catch. While this new promotion waives the upfront cost, the monthly payments have gone up in some cases. The Samsung Galaxy S4, for instance, is currently available for $149.99 upfront and $20 monthly payments for 24 months. Starting on July 27, however, the smartphone will require no down payment but the subsequent monthly payments go up from $20 to $25 for 24 months. That means that the current total for the device amounts to $629.99, while the total starting on July 27 will be $600. It's still a price drop in this case, but the savings initially appear to be of $149.99 (the down payment), when in fact they are just $29.99. It's still a good deal, but it's best to know all details and implications before making any investment.