This promo was a product launch promo that lasted only few first months. What I vaguely remember is that in addition to Apple's limited time trade in credit, T-Mobile offered additional $500 via 30-month statement credit, bringing the iPhone 13 Pro 128GB price from $999 + tax to about $80 + tax. If you have Magenta Max plan, T-Mobile will offer up to $800 credit for trading in iPhones toward the new one every 24 months.wait what really? I'd do that. I have Tmobile but I always buy my phones out of pocket from apple. how does this promo work ?