4 T-Mobile
While the Un-carrier is not currently offering any specific deal on the iPhone 8, T-Mobile says it will offer customers a credit of up to $300 when they trade in their iPhone 6 or newer (has to be in good, working condition, of course). Unfortunately, this credit is applied in the form of monthly installments that will be issued over the course of 24-months. T-Mobile is also offering Apple Watch Series 3 buyers a $30 credit towards their first three-months of LTE service. The cost of LTE on Apple Watch S3 is $10/month thereafter.