Let’s suppose that you don’t have a long distance phone plan and you want to call a friend out of state…. This is as simple as visiting viatalkfree.com website and initiate the phone call.
Since the website requires entering two US numbers, both you and your fried have to be in US. Anyway, with a little effort you can call your friends in US even if you are living in Europe. All you have to do is to obtain a free US DID number ahead of time.
For alternatives ways of calling for free US numbers, check also this post.