P.F.
We had Vonage and we liked it a lot. They just announced free international calling. I don't know if that is for a short time or not but they are not one of those companies that lures you in and then changes things. They pride themselves on keeping things the same. We did get rid of it but only because we disconnected our house phone completely we went all cellular. It saved even more.
My mom uses one of those cards. It is a bit confusing but very very cheap. YOu have to type in a phone number, then the number you want to call and then a long number for your account. She swears by it.