So, you want to call a landline number or a mobile number in the US or Canada? You can, and for free. With that said, I'd like you to try it out and stop reading! And Google this: 'free us and canada calls through google hangout'. An updated iOS device will be required. Okay, I'll make it even easier. Just glance the quote from engadget.com below.
"Calls to the US and Canada are currently free from Hangouts -- regardless of where in the world you live. So if you're in another country and want to call a phone in the US, use Hangouts."