Great question — answering as the UphillTech team:
International phone connections are usually ridiculously expensive. The best option is either to use SIM dedicated for international calls (like Lebara, no idea if it's available in Canada) or use VOIP services like Skype (effectively, Lebara etc. are VOIPs). So your option is to buy any SIM card with good data package and configure App for voip calls and fill it with enough credits. You're unlikely to find anything cheaper.
Full answer by Cjxcz Odjcayrwl: https://travel.stackexchange.com/a/119077 (CC BY-SA 4.0).
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