If you use your phone hardly at all, you will likely find it cheaper to go with a US sim card, such as Telestial (eKit Simple Calling). American mobile phone service providers have the advantage of not charging 911 fees, not charging taxes, not charging system access fees, and not charging other hidden fees on prepaid customers.
You will have a US number though, so if you will have a lot of Canadian people calling you then maybe not a good idea because it will cost them more. However for an emergency phone only, it's perfect since there are no recurring monthly charges. Also you use Rogers network in Canada which is very strong, and your roaming costs when in the US, Europe or any other country will be far cheaper than with any Canadian provider. Technically you will be roaming 100% of the time you are in Canada, yet still I find it cheaper than using a Canadian company (prepaid cell phone service costs in Canada are that high!).