You pay the full price UP FRONT, then over 2 years, they pay you back the value you paid.
Only downfall is, if you want to upgrade NEXT year to the next model, you're basically screwed. That is why Im going the Apple Upgrade Program route.
No, you sign the EIP and the monthly amount due per the EIP shows up on the bill along with a credit every month for the next 24 months. You have to stay with T-mobile the full 24 months or the remaining payments are due.
Both Verizon and AT&T have instituted matching programs using bill credits to keep you tied to them.
There is NO pre-payment required. Models beyond the base iPhone 7 require additional payments . Max credits over 24 months=$649 on T-Mobile.