I have used Google Talk for a year now for FREE. If you look at their rate plans the USA and Canada are free. I guess because they are an AMERICAN based company. All I know is, I found out about it after digging into googles "extra" services, just exploring. After that I have been a 100% Google Fan!!
I had a phone Number for 4 years with Sprint. I ported that number to Google Voice for $20.00. then in the settings I forwarded the calls to multiple phone lines. house, cell. After a month I found an app on Google Play called "Bring Ring" for $5.00. It allows you to access the phone numbers setting in Google Voice. So I am able to turn off either or all numbers if I chose. that's not even the best part, Every Android user has a Google email account already that they're contacts are in.
In Google Voice, go into each individual contact and create personal greetings for each one.
Example: My Dad calls, My Google Voice Voicemail says, " Hi dad, sorry I missed you, I'm probably out with the kids, if it's important call me again or leave me a message".
I also have a general one for selected groups such as co workers/ bosses.
That way you can say on your voicemail to your friends group, to meet you at the lake for fishin' (WHILE YOUR SUPPOSED TO BE WORKING, LOL)
I have paid Google only the 20.00 since August 2012 for excellent phone service VOIP (voice over internet protocol)
Google's app called "Hangouts" is linked to your Google Voice and Gmail account and the quality is comparable to Skype but it is FREE! that is unless Microsoft buys out the technology but I seriously doubt that.
One thing they may do is charge people to assign Google voice numbers, who knows. I'm reaping the benefits now!
RaZZoREdgE