Verizon offers iPhone promotion that gives you the newest model every year
If you purchase the Apple iPhone 6s or Apple iPhone 6s Plus from Verizon tomorrow using the carrier's Device Payment option, you will automatically have the choice to trade in your iPhone 6s or iPhone 6s Plus for the Apple iPhone 7 or Apple iPhone 7 Plus next year. With that option, your 24 month installment plan starts over on the new model. If you decide not to make the trade, you can continue making the installment plan payments on your current phone. After 24 months, that device is yours.
Verizon's iPhone pricing schedule offers the 16GB Apple iPhone 6s for $0 down (qualified subscribers only) and $27.08 a month over 24 months. The 16GB Apple iPhone 6s Plus is also $0 down, and $31.24 a month over 24 months. The 16GB iPhone 6 is $0 down and $22.91 a month over 24 months, while the 16GB iPhone 6 Plus is $0 down and $27.08 a month over 24 months. Lastly, the Apple iPhone 5s is $0 down and $18.74 a month over 24 months.
If you're coming from another carrier, make the switch, trade-in your old smartphone, and get up to $400 from Verizon in the form of a $300 gift card and a $100 bill credit.
source: Verizon (1), (2), (3)