Fast forward to today, and Sprint has bumped the offer again, so folks who are willing to lease the 64 GB iPhone X for 18 months with Sprint Flex can get it for just $20 per month and $0 down (instead of $41.76 per month). The deal requires a new line, but no trade in is needed. Keep in mind that leasing the phone means you have to return it to Sprint after 18 months unless you want to pay the difference to cover its full cost.
Still, $20 a month is nothing to peruse an iPhone X, conditioned only on the fact that you need to have good Sprint coverage where you live or travel. Also, if the merger with T-Mobile goes through, you might be on the receiving end of a better coverage, too, and a deeply discounted phone, albeit one that might be discontinued very soon.