I guess I went a different direction with Google Voice. Best case my "home" line was a $25/mo VoIP line. $40/mo with the various Ma-Bells for a basic / barely use it line.
Then I ported existing home number first to Sprint (which was on some obscure VoIP provider which had ported it from at&t where it originated). Here I played a gamble as I already had an existing account with Sprint (wife's cell, I use wifi another GV# for mine w/ no issue). NOT having an account here would have seriously cost me [~$200]. Technically they could have charged me. $0 cost.
This could have just been a easy one step port, but because I was off on some unknown telco Google wouldn't port from I had to do it. Lost one day.
The moment the number went active / worked on the cell I initiated the new number request / port [one time $10 fee] with Google Voice for that number. It worked one day on the cell, and the next on Google Voice.
Then added Google Chat as a forwarded call line.
Bought the Obitalk device and configured it. One time fee $50. So for sixty dollars or within three months the move has paid for itself [so far :-].
Setup a free account ObiTalk at https://www.obitalk.com/ -- needed to configure the device...
So far Google / ObiTalk are $0/mo. EITHER one could change the terms and/or just cancel service with little to no notice. No notice with Obi and I'd just have to port my number someplace else. Same if Google cancels service (though they're good about notifying you). Problem: WILL Google port numbers out. Technically they are not a "telco" and I'm sure there's a loophole allowing them NOT to. Betting on "Do No Evil" here with my 30 year old phone number. Yes. It. Is. Cool.