One of T-Mobile's flagship offerings is their MyFaves feature which allows free calling to a certain amount of people on any network. It's a fairly popular aspect of T-Mobile and according to some customers, it is now being offered (for a limited time only, of course) as a free add-on!
We're not sure about the exact specifics necessary in your rate plan, length of contract, etc. in order to receive MyFaves for free but it's definitely worth calling T-Mobile and checking it out. From what we're hearing, a lot of folks are receiving it but some aren't so lucky. Let us know in the comments if you do try to add MyFaves for free!