T-Mobile offers the Apple iPhone 6 16GB Smartphone bundled with a SIM Starter Kit for Space Gray, Silver, or Gold for $15 up front then $24.08 per month for 24 months via coupon code "THUNDER72". (That's a total of $592.92, or $72 off). Also, free shipping applies. It features an Apple A8 processor, 4.7" 1334x750 Retina display, 8-megapixel iSight camera, and 1080p video capture with 60 fps video shooting (240 fps shooting at 720p slow motion playback), 1.2-megapixel FaceTime HD camera, 802.11n wireless, and Bluetooth 4.0.

Of note, the coupon also cuts $72 off all iPhone 6 models at T-Mobile.