Moments after Apple announced the new iPhone 8 and iPhone X on Tuesday, T-Mobile CEO John Legere tweeted that the carrier would offer up to $300 off any new iPhone for trading in an old one.

T’s one big catch: The $300 credit will be broken up over a 24-month installment plan.

So instead of getting a $300 credit up front for trading in an old iPhone for a new one, T-Mobile will award $12.50 in credit each month for two years.

The promotion applies to any iPhone 6 or newer in good working condition that’s traded in for an iPhone 7 or newer, T-Mobile clarified Wednesday on Twitter.

Like other carriers – and Apple itself – T-Mobile is pushing customers to pay for their phones in monthly installments.

If you’re looking for money up front, research what the going rate is for your old iPhone on websites like Gazelle before making the final call.

Preorders for the iPhone 8 begin Friday, and iPhone X preorders begin October 25.