Sprint & T-Mobile offer free iPhone 7 with trade-in, Sprint knocks $100 off 256GB model

The T-Mobile deal, beginning Friday at the same time as Apple preorders, requires that people trade in an iPhone 6 or 6s, earning up to $650 in credit to be spread across monthly bills for two years. People wanting extra storage or a 7 Plus will have to pay the difference, and cancelling service before the two-year mark will force customers to pay a device's full cost.

The Sprint offer is only slightly more flexible, allowing people to trade in not just an iPhone 6 or 6s (including Plus models) but alternately a Samsung Galaxy S7. Otherwise, customers are still expected to stay on for two years and get paid in credit.

Sprint is also offering a separate $100 discount off 256-gigabyte iPhone 7 models, bringing their cost down to $749. That pricing will only be valid during the preorder phase, and then only until supplies are exhausted.

The iPhone 7 and 7 Plus will ship on Sept. 16. Both feature upgrades like faster processors, increased storage, and better displays and cameras. The 7 Plus includes a second camera for 2x optical zoom.