Buying a SIM card in Canada?

Is it possible to buy a SIM for an unlocked phone? My phone is unlocked but it's a US-only plan, and roaming is not offered. In the past I've bought international SIM cards, which were great with my old phone, but not so great with my smartphone. I was hoping I could buy a prepaid SIM somewhere in Halifax. Or Montreal if I wait for my second trip to Canada.

Of am I stuck dealing with one of those online sellers who all sell the same international SIMs?

On the West Coast.... you can walk into a gas station or 7 eleven to get a SpeakOut product....

http://www.speakout7eleven.ca/prepaid-cellphones

I notice on the site there is a SIM there.

There are cell phone booths all over and most have pay as you go plans. For coverage, Bell is excellent.

This location is not far from where you dock and is across from the wonderful new central library which is well worth visiting. It is also on the way to the Public Gardens: http://storelocator.bell.ca/bellca/en/NS/Halifax/Bell-Aliant-Cornwallis-House/BA268

https://www.tripadvisor.ca/Travel-g153339-c163066/Canada:Mobile.Phones.In.Canada.html