T-Mobile has announced that for a limited time it is bringing back its fourth line free promotion under the 10GB for all plan. The offer is the same as it was, families with four lines can get the fourth line free of charge, and each line gets 10GB of its own data. That's right, for $120 a month, you get four lines with unlimited talk and text, and 10GB of data each.

In addition, you can take advantage of T-Mobile's other great features with this plan, like unlimited calls to and from Mexico and Canada, Wi-Fi calling, unlimited music streaming on various services and even unlimited in-flight texting with Gogo. T-Mobile does note that this promotion is only back for a limited time, but it will remain on your account for as long as you are a customer if you make the switch. If interested, be sure to give them a call or head to your local T-Mobile store to make the switch.

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