So how does the $300 come off then? If I trade in my iPhone 7+ 256GB in damn near brand new condition, does it JUST take payments off the monthly payments, or can it go towards the down payment? I mean that would be nice, but I don't know if T-Mobile would be willing to do that. When I switched earlier this year, they let me trade in my iPhone 7+ from AT&T and they applied the value it was worth towards the down payment. I got another iPhone 7+ but this time through T-Mobile. Only thing I had to do was pay taxes on it. Maybe I lucked out because I was just was coming on to T-Mobile? I dunno. $430 is a lot to pay for a down payment not to mention taxes and the sim? Your probably looking damn near $550 just to get the X no?