Remember last month when T-Mobile kicked off a Buy One, Get One deal on several flagship smartphones? Apple's iPhones were only part of the deal for around 10 days, but they're making a return tomorrow.

Starting December 21st, T-Mobile will offer a BOGO deal on the iPhone 7, iPhone 7 Plus, iPhone 8, and iPhone 8 Plus. You'll need to add a new line and buy both phones on EIP to get this deal.

Once you've met those requirements, T-Mo will send you a prepaid MasterCard card to cover the cost of the cheaper phone. That rebate is worth up to $700, which means that if you get two iPhone 8 Plus phones, you'll end up paying $99.99 for the second device.

T-Mobile is also bringing back its iPhone X trade-in deal. You can get $300 off an iPhone X when you trade in an iPhone 6 or newer (iPhone SE doesn't count) and buy the iPhone X on EIP.

These deals will be available in stores and online. They'll only be valid through end of day on December 24th, though, so you'll have to hurry if you want to take advantage of them.