You should get a free Google Voice number. Get the Google Voice app, which will work seamlessly on an Android and some other phones - so you can route Canadian calls via Google Voice. Calls to all U.S. AND Canadian numbers are FREE. Routing calls by GV to other countries are as low or lower than any other discount carrier. 2¢/min. to landlines in many countries. Of course calls to cell phones outside the U.S. and Canada cost extra.
I didn't know TM (or anyone else) had a "call Canada" plan.