I thought this deserved to be on the deal page since it's a limited time offer.
T-Mobile is offering their family plan for $100 a month for 2 lines for truly unlimited 4g, texts, and calls. Additional lines are only $40 dollars each!
As their usual plan, it comes with international text and data and whatever available add-ons, like unlimited international calls.
Living in NYC (service is great here, I count account for people in suburban places), I made the switch from Verizon three months ago because I was sick of getting different bills every month, with t-mobile I am paying the same thing every month and they matched me for their new offer today!
I also would not recommend signing a contract with any carrier right now as prices are most likely going to keep going down for the next few years to match European pricing. T-mobile (as well as other carriers) offers the advantages of post paid without being tied to them or to a specific plan, you can change every month to suit your needs.
Lastly, Sprint which is its major rival (Verizon and AT&T consider themselves too high to compete with Sprint and T-Mobile) also does offer cheaper plans than before, but first I find their service to be rather bad and also when you get let's say a T-Mobile iPhone, it's resale value will be much higher since it's virtually usable on any carrier worldwide.
Link to the offer:
http://www.t-mobile.com/cell-phone-plans/family.html