1/4 year in Canada

I'm wondering if anyone has advice:
I come to Canada for 3 months a year, every year. I'd like to have a phone for calling within Quebec. What is my cheapest bet? (I have a verizon phone from the states and am afraid the roaming charges will be prohibitive). I don't really want to get locked into a monthly rate or a contract, so maybe some sort of prepay situation. I'm grateful for any thoughts.

You could always get a Rogers or Fido prepaid card. Fido is pretty good in metro areas such as Montreal (its corporate home). I'm not sure, but I think the simcard becomes invalid after the account becomes dormant. Everytime I goto Canada (once a year or more), I end up having to get a new simcard for 35$ (or was it 25$ now?). Prepaid is not cheap compared to your usual monthly packages.