Sprint announced Friday that it’s offering a limited-time buy-one get-one deal on the iPhone 6s and iPhone 6s Plus, so long as you’re a new customer singing up for a new line of service and have an upgrade available.

You won’t necessarily walk out of the store with a “free” iPhone 6s or iPhone 6s Plus; rather, the price of the phone will be discounted across your monthly bills until it’s fully paid off. Here’s how Sprint explained in an email to TechnoBuffalo:

This is how it works:

  • First iPhone 6s (16GB) is  $27.09 per month with 24 monthly installment bill payments with $0 down – the second one is free after $27.09/month service credit!
  • First iPhone 6s Plus (16GB) costs just $31.25 per month with 24 monthly payments with $0 down – the second one is free after $31.25/month service credit!

You don’t have to do the 24 monthly installments, though. Sprint said you can also lease one with an 18-month lease payment, or lease one iPhone and buy the other one outright. “Either option will get a monthly offset credit for the second, lower-cost device,” Sprint said. The deal starts today, no word on when it ends.