T-Mobile will let you knock $1,200 off an iPhone Duo — here's how to get it

(Image credit: Tom's Guide) The iPhone Duo is proving very difficult to get hold of, and it seems the high price tag has not made the foldable any less desirable. Well it might end up on a few more wish lists, now that T-Mobile has just increased the amount of money you can save on iPhone Duo when you trade in your old device.Previously T-Mobile offered up to $1,000 of trade-in credit when you ordered an iPhone Duo. Now that figure has been increased to $1,200, and the best part isn't that it's an "any-condition" trade-in offer; it's that you can snag the same discount and keep your existing device. You just need to sign on for the right plan.If you plan on trading in your old device for an iPhone Duo, you should be aware that T-Mobile has a particular list of phones that will actually net you the full $1,200 credit. The bad news is that it's limited to Apple and Samsung handsets; the good news is that it doesn't require you to trade-in something fairly new.In fact, the oldest eligible iPhone is the iPhone 15 Pro and Pro Max, while anyone rocking a Samsung Galaxy S24+ and Z Flip 5 (or newer) can also claim that sweet discount. Considering some of these phones are now coming up to three years old, it's not such a bad deal. More so when you consider that many of them actually sold for less than $1,200 in the first place — including the iPhone Air, which is currently $300 off at Best Buy.Other trade-in thresholds include $930 and $500 off, with some of those devices dating back several years. This is probably more than you'd get by selling them on the used-phone market. Like most trade-in offers, this is applied to your account as 36 monthly credits (Image credit: Tom's Guide)That said, you do also need to sign up for the right plan. New customers have to sign up for Experience Beyond 2.0, with prices starting at $100 a month for a single line. Existing customers can sign up for Experience Beyond 2.0, Experience Beyond or Go5G (from $75 a month).But what about if you don't want to trade in? Well, you'll need to activate a brand new line and port your number from an eligible carrier in the process. Again, this requires new customers to sign on for Experience Beyond 2.0, while existing customers can choose between Experience Beyond 2.0, Experience Beyond or Go5G. It's not specified which carriers are eligible, so you'll have to go through the process and check.Sadly, the elephant in the room is that you will be waiting a while for your iPhone Duo to arrive. T-Mobile's delivery estimates are now listed as December 31 to January 6, which means you're unlikely to get your handset before the end of the year. It doesn't matter which model you buy either, all colors and storage variants have the exact same wait time.That said, since the iPhone Duo is very expensive, you shouldn't miss the chance to save $1,200 on the total price. Even if it does mean signing up for an expensive 3-year contract with one specific carrier. Follow Tom's Guide on Google News and add us as a preferred source to get our up-to-date news, analysis, and reviews in your feeds. Sign up to the Tom's iGuide weekly newsletter with coverage on everything from product launches to software updates, this is your go-to source for the latest updates on all the best Apple content. Tom is the Tom's Guide's UK Phones Editor, tackling the latest smartphone news and vocally expressing his opinions about upcoming features or changes. It's long way from his days as editor of Gizmodo UK, when pretty much everything was on the table. He’s usually found trying to squeeze another giant Lego set onto the shelf, draining very large cups of coffee, or complaining about how terrible his Smart TV is.