T-Mobile said it will drop the Jump On Demand lease payment for the 16GB Apple iPhone 6s to just $5 if customers trade in an iPhone 6. Customers who trade in an iPhone 6 Plus can lease the 16GB iPhone 6s Plus for $9 per month. Without the trade-in, the lease payment is $20 per month for the 16GB 6s. T-Mobile says the out-the-door cost is $0, and the full price of the 16GB iPhone 6s totals $523.99 for customers who remain with T-Mobile for 18 months. By way of comparison, Sprint's iPhone lease program costs $15 per month with a trade-in or $22 without a trade-in. T-Mobile also said it will sell the Apple Watch Sport beginning Friday, Sept. 25, the same day the iPhone 6s and iPhone 6s Plus go on sale. T-Mobile is offering the wearable for $0 down and 24 monthly payments of about $14.50 for the 38mm Watch Sport ($349) and $17 for the 42mm Watch Sport ($399).