First of all download FriendCaller from here.
After it is fully installed, open friend caller from desktop. Then register. I recommend you to use temporary email for the registration, like yopmail.com
Then go to your email and confirm your account and you will be credited $ 0.10 for free calls. So you can only call for 10 seconds for free but this what I made this tut so you can call free.
Now login with your account.
Then click on the phone icon.
Now comes the great part. Download a software called Cheat Engine from here.
Run the software and click on "Open Process".
Then click on window list.
Select friend caller, and open it.
Now dial number in friend caller. [First test your own number] and click call.
Now in Cheat Engine, enable speed hack. Edit speed to 0.00
Now enjoy your call. The timer will freeze. You can talk as much as you want. When you finish call, you will be only charged 0.02 but after your balance is finished, make new account and enjoy.
If you have any doubts please be free to comment