Unlimited Voice and SMS to other carriers is expensive. Look at Twilio's pricing or Skype's pricing, or any other voip provider. Text and calling to your own network is essentially free, but off network gets expensive. Granted, I don't know how big of a cut these voip providers take, but I can't imagine it's that high.
Edit: Just want to point out, I'm not saying this is a bad bet to make. They can attract a ton of consumers with a super low cost, and if those consumers do most of their communication in-network, eventually they'll be in the green.
I don't know the financial breakdown, but it's worth noting that Bandwidth.com — the company behind Republic Wireless — actually runs the VoIP backbone that powers Twilio, Google Voice, and other services. So I'd imagine they get a better rate :)
"Bandwidth.com, Inc., a privately held telecommunications company in Research Triangle Park, North Carolina, announced today that it has signed a commercial deal with the Verizon wireline companies under which the parties agree to terminate each other's VoIP traffic at a rate of $0.0007 per minute."
This is for landlines, but still a much lower number than I was expecting to see.
Put it together with usage data, you quickly get over $19: http://blog.nielsen.com/nielsenwire/online_mobile/u-s-teen-m...
Edit: Just want to point out, I'm not saying this is a bad bet to make. They can attract a ton of consumers with a super low cost, and if those consumers do most of their communication in-network, eventually they'll be in the green.