I'm looking for a provider with no recurring fees. I would add credits as I need them.
So far most providers I've seen are selling packages with monthly fees, but that's not what I'm looking for.
I just need an account which I could add credits and place calls from my Asterisk pbx.
Another cool feature would be the ability to test the service before I sign up, i.e. some free seconds for new users etc. It's also important they support lots of international calls. Just outbound traffic.