https://www.cnet.com/news/cyber-monday-2018-iphone-deals-iphone-x-xr-xs-xs-max-free-iphones/

If you're upgrading your current phone on Verizon, the carrier will snip $100 off the asking price of any iPhone with an "X" in its name -- as long as you hand over your previous phone. However, if you're switching from another carrier, or adding an additional line of service to your account, that discount rises to $300. Once again, you'll need to trade in your old phone to get the sale.

This offer replaces a much better deal to buy one iPhone, get an iPhone XR, or take up to $750 off any "X" iPhone.