Black Friday 2018 phone deals: Free OnePlus 6T now, LG V40 with free $500 TV, Moto G6 for $200
https://www.cnet.com/news/black-friday-2018-deals-free-oneplus-6t-now-lg-v40-free-500-tv-moto-g6-200-palm/
Also see Black Friday deals specifically for the iPhone XS, XR and iPhone X, the Galaxy S9 and Note 9, the Pixel 3 and 3 XL and T-Mobile's Black Friday promotions.
If you already have one or more phone lines through T-Mobile and add another and trade in an old phone, the carrier will give you a new OnePlus 6T phone to use for the additional line. This is one of our favorite phones for 2018 for its excellent performance for the price. A price of "free" is even better.