This appears to be confirmed, seeing as T-Mobile's own Mike Sievert published a blog post about it this morning. After many rumors and leaks, it looks like T-Mobile will indeed start selling accessories on EIP. For those unaware, EIP stands for Equipment Installation Plan. Which means you'll be paying a monthly fee for these accessories until they are paid off. Much like their smartphones and tablets. So say you want an Otterbox case for your brand new Samsung Galaxy S5 or LG G3, you'll be paying a specified amount each month on top of your bill. However, this only applies to accessories that are priced between $69 and $250. So that means that you won't be able to get your $20 case for free and pay it off over 24 months. And yes, it's 24 months. I was hoping it'd be a shorter time since they should be cheaper than devices. Here's an excerpt from Sievert's blog post.
"This means you and your family could walk out the door not only with new smartphones and tablets but also with your choice of the latest audio and mobile accessories–all for $0 down and 24 monthly payments with a Simple Choice plan. For example, you could pick up the state-of-the-art LG Tone Pro hands-free headset for $0 down and just $2.91 a month for 24 months with absolutely zero interest. You can find more information about T-Mobile's new EIP payment option for accessories at your nearest participating T-Mobile store."
I like the product placement of the LG Tone Pro headset there though. Now it's interesting to see that it only goes up to $250. It looks like if you want to buy something that's $300, you'll have to pay a down payment to cover the difference, according to TmoNews. This might be T-Mobile getting ready for the onslaught of wearables, specifically Android Wear. Because I'm sure they'd sell plenty more if they offer payment plans than selling them for $200 as the only choice.