T-Mobile has shared the full details of its new JUMP! On Demand promotion that offers the iPhone 6s and iPhone 6s Plus for as low as $5 and $9 per month respectively with a qualifying smartphone trade in. The exact monthly payment is calculated based on both the iPhone model purchased and smartphone model traded in.



A base 16GB iPhone 6s starts at $5 per month with zero due upfront when trading in an iPhone 6, iPhone 6 Plus, Galaxy S6 Edge+, Galaxy S6 Edge, Galaxy S6 or Galaxy Note 5. The price rises to $10 per month with an iPhone 5s, Galaxy S5 or Galaxy Note 4 trade in, or to $15 per month with the trade in of most other smartphones.



A 16GB iPhone 6s Plus starts at $9 per month with zero due upfront with an iPhone 6, iPhone 6 Plus, Galaxy S6 Edge+, Galaxy S6 Edge, Galaxy S6 or Galaxy Note 5 trade in. The price rises to $14 per month with an iPhone 5s, Galaxy S5 or Galaxy Note 4 trade in, or to $19 per month with the trade in of most other smartphones.

The promotion also offers the iPhone 6s and iPhone 6s Plus in larger storage capacities, but upfront payments of $99.99 or $199.99 are required for 64GB or 128GB models respectively. The monthly payments for the new iPhones are $1 cheaper for 64GB models and $2 cheaper for 128GB models compared to 16GB pricing.

Each payment must be made for 18 months, at which point the iPhone 6s or iPhone 6s Plus must be returned in good condition. T-Mobile offers the option to pay an additional $164 to keep the iPhone, bringing the total cost to $524 for a 16GB iPhone 6s -- a savings of $125 over the device's full retail price through Apple.

T-Mobile also has a non-trade-in JUMP! On Demand promotion that offers the 16GB iPhone 6s for $20 per month, or 16GB iPhone 6s Plus for $24 per month, for 18 months with zero dollars paid upfront. As with the new trade-in promotion, 64GB and 128GB models are available with upfront payments of $99.99 or $199.99 respectively.

T-Mobile will honor these deals for customers who already pre-ordered an iPhone 6s or 6s Plus with a trade in by issuing an upfront bill credit.

T-Mobile will begin selling the iPhone 6s and iPhone 6s Plus on September 25.

Update: T-Mobile has also confirmed it will begin selling the Apple Watch on September 25 as MacRumors previously reported. Apple Watch Sport models have the option of 24-month financing.