Renting. It's $57 per month for 24 months and then you have to hand it in.
So you pay $1368 for the privilege of using the Duo for 2 years.
You get the choice to pay the remaining value of the phone and keep it, or enter a new "lease" agreement for a brand new phone at the end of the term. The formula is simple:
purchase fee = device list price – lease payments made – remaining discounts or trade-in credits.
If you're paying $1368 over 24 months, you could pay the remaining $632 after those 24 months and keep it with 0% interest.
Lease. You can buy it out at the predefined price at the end.