T-Mobile brings back its iconic referral discount, but there’s a catch

Credit: Joe Maring / Android Authority TL;DR Existing T-Mobile subscribers can now share a 10% lifetime voice line discount with friends and family directly through the T-Life app. Unlike traditional 20% Insider Codes that required employee connections, this 10% discount is available through the general customer base and stacks with standard phone trade-in or Keep & Switch offers. To qualify, switchers must port in a number from a competitor (like AT&T or Verizon) within 14 days of checkout.