It looks like T-Mobile will be bringing back the family plan goodies again this year. According to TmoNews, starting July 1st new and existing T-Mobile customers will be able to avail themselves of a "Back-to-School" promotion. This promotion, which can be adopted anytime between July 1st and November 13th, will reduce the price of certain family plans by $5 a month until January 2014.
To make this promotion kick in, existing customers will have to extend their contract with T-Mobile for 2 years (for all the phones in the plan). On the other hand according to TmoNews this rate plan change does not affect your upgrade date for a new phone. For more details, you can look at the coverage on the TmoNews site by clicking here.