As many had speculated, OnePlus is offering its brand-new 6T on T-Mobile. This is the Shenzhen-based company's first venture into US carrier partnerships, and to spice things up, T-Mobile is offering $300 towards the 6T with the trade-in of any one of 33 phones. That $300 figure doesn't make a whole lot of sense for the newer flagships on the list, but for the older ones, this could be a great opportunity to get a nice discount.
— OnePlus (@oneplus) October 29, 2018
You can see the full list in the hero image above, but here are the basics. Every OnePlus phone is eligible, which is a nice loyalty bonus. Apple phones going back to the iPhone 6, Samsung flagships from the S8 to the S6, all previous-gen Google Pixel phones, LG flagships from the V30+ to the G6, and Motorola's two Z2 phones (and the Nexus 6, for some reason) can be used to take advantage of this. Likely knowing that nobody's trading a brand-new iPhone XS Max or a Pixel 3 XL in, T-Mobile didn't bother including flagships from the current generation, so the $300 offer is pretty good for most of the phones on there.
$300 is roughly 50% of the OnePlus 6T's MSRP, so this is definitely something you should look into if you're a T-Mobile customer and want a 6T.
Promotion ends today
According to T-Mobile's page for the offer, the promotion ends today, November 8th. So if you were hoping to take advantage of the sizable $300 discount available when trading in an older OnePlus phone, you've only got the rest of the day to grab it.