How to call USA & Canada for free from other country
Once you log in into your Gmail account, in the bottom left corner you will see " Call phone " button. You clock it and on the bottom right corner you will see the pop up window with digits. From there you choose the country you want to call. As i mentioned before, USA & Canada is free, for the other countries you have the rates shown next to the flag when you choose it. Now you just dial the country code USA is +1 and the rest of the number.
I have personally tried it and it works perfectly. By my opinion, Google may change this policy each year, but for now it is free and lets use it while it lasts. Anyway the fee is low so you can also use it to call other country as well. It shows the cost next to any country flag when you select it.
You can see this article and many more on my blog post as well.
Thats it !! Enjoy your free calls.