I finally purchased a phone card in Canada, which was resonable. My T mobile cell worked in the Banff-Jasper area, but the mins. were costly, so I mostly used pay phones for my Alaska trip this summer
In Alberta and British Columbia last summer my Verizon worked OK but my partners AT&T did not work. Also went to James Bay last summer going through Ontario, Quebec, and New Brunswick and basically if a Canadian phone worked mine worked. Just look out for the out of country ding you will get.