You can take over 70% off a second iPhone X with this deal.
Brad's Deals Editor Michael,
New customers can bring their number to T-Mobile and purchase two iPhone 7, 7 Plus, 8, 8 Plus, or iPhone X devices on at least one new Mobile ONE or Simple Choice Unlimited plan to receive a rebate equal to the price of one of the phones (and/or totaling $700). You'll need to submit the code 18Q1APLBOGO at T-Mobile's rebate page after you make your purchase to claim your prepaid MasterCard rebate. For select phones, like the iPhone X and iPhone 8 Plus, you'll still need to put money down today, but the remaining balance you'll need to pay over the full plan period will drop to just $20. Taxes and SIM kits will be charged for each phone and will be due today, but the shipping will be free.