How can I make phone calls without a cellular plan?

Episode 1441 (1:37:22)

Bernie from Washington State
Verizon JetPack

Bernie wants to know about his data. He's worried that he's going over his data caps. Leo says that cell phone companies are moving towards Voice over LTE, which will use data to do phone calls because the quality is better. Can he get a data only device and do that? Leo says he can use apps like Tango and Skype to do that, but he's still paying for data. No cell company offers a mobile phone with just data only. He could always buy an old phone from eBay and do it with a MiFi device, like Verizon's JetPack. There's also FreedomPop.