How can I make Wifi phone calls to regular phone lines (Canada) ?

Hi,

Is there a way I can make phone calls with Gmail on my Moto G? I am in Canada.

I have a very limited calling plan (by choice). So when I travel, I always take my laptop with me to call my family, who don’t have wifi. I connect to wifi, open Gmail, and click on the little phone. Then I can call anybody to their regular phone line. I would like to stop carrying my laptop if it is possible to do the same with my phone.

On my Moto G, Gmail does not show the little phone.

I was wondering what was the name of the app, and was told it was Google Voice. Unfortunately, my experience in Google Store is often complex. I understand Google Voice in not available in Canada (?).

I finally found «Google Voice», blue pic, June 12 2014, in the Google Store, thru my PC. But it says : App not compatible with any of your devices, «Currently only available in the US». (https://play.google.com/store/apps/details?id=com.google.android.apps.googlevoice).
So I downloaded a few apps, but they are really far from Gmail :
– PHONE for Google Voice & Talk (GV Phone) : works but volume is very low.
– Viber : I can only call people with Viber
– Talkatone : downloaded the app and says it is not available in my area (Montreal, Canada).
– Vonage : asks me to pay.
– Tango : the phone pic is displayed but grey, hence not accessible (and Tango looks rather like a social network…)

Anyone can help?
Thank you so much.