T-Mobile is offering a FREE 3rd Line for New & Existing Customers via bill credits (limit 1 offer per account). To qualify, existing customers will need to have a qualifying credit and be part of the Essentials, Magenta or Magenta Plus plan. New customers will need to activate two voice lines to get the third free. Credits may take up to 2 bill cycles and will stop if you cancel any lines. Spread the word!