misskatpaw

FaceTime Audio for other Apple users when on wifi.
Rebtel for calling UK landlines from my cell.
Our Telus landline package has free international calling.

BritBC

If I need to call a phone number in the UK I add money to skype and you can call landlines/mobiles at a pretty low cost. If not just skype-skype calls.

Anna Maria

FB voice & video calls - free
Koodo with my monthly plan for $3 extra I get super cheap rates to Europe like 1h will cost me just under $1

daveincolchester

As far as calling a Canadian bank for free.
Last year I was in Panama and was having a problem moving some money down here.
I called the free number on my CIBC Visa card and asked to be put through to my local branch in less than a minute I was talking to Lisa from my local CIBC branch.
Free.

Freshwhyte

I use T-Tag when I call the UK. You send a text message of the number you need to call (ex 441416948765) to 647-800-000. You'll receive a text message back with a local access number to call. You can try it out for free (I think you get 5 free "tags" at 60 minutes each) at www.ttag.ca

The wanderer.

I can't tell you how to call to the UK for free but i can tell you how to call to Canada for free.