This past September T-Mobile launched one of its most aggressive promotions with the “Kids Are Free” family plan promotion giving you the ability to add up to 3 people to your Family Plan account for free (until January 2012) with a qualifying rate plan. Well today is the last day of that promotion and beginning tomorrow, it will be replaced with a $5 add-a-line offer. Starting tomorrow, customers with Even more rate plans will be able to add an additional line for only $5. The $5 add-a-line promo will be available to both new and existing Even More customers and will require a 2-year contract extension for each line on the account.

Qualifying rate plans include the 750/1500/3000 minute Family Even More plans but of course the unlimited plans will not qualify.