I make about 80 national calls per month and I use my VOIP as a second phone . The reason that I am asking you this is cause my BB provider (f2s) is about to do away with my VoIP service .
Skype is the best VOIP service by far. More than 6 million users use this service online.Its highly popular and they don't over charge you for calls there very reasonable.If you ever need any help customer support are always fantastic too.