https://www.cnet.com/news/buy-an-iphone-8-on-sprint-get-one-free-dec-2017/ >Or, if you'd rather take a savings, you'll be able to knock $300 off the bill of the same iPhone 8 or even an iPhone X when you trade in your old device. Those trade-in savings keep pace with November's Black Friday deals, and with other carrier offers during this holiday crush. >The fine print on Sprint's buy-one, get-one offer: