I always just pick up local SIMs with unlimited data in whatever country I visit. Usually between US$20-$60 per period/month. The SIM itself is free in many countries. Make sure your phone is unlocked so you can insert other SIMs.
The shop in the the thread below might have SIMs for Canada also. It has information for getting a SIM in Taiwan before going to USA.
I googled “temporary (or tourist) Canada SIM” and found a lot of information but I don’t know Canada service providers well enough to make any suggestions.