Stongly suggest you to use FIDO.I got a cute SonyEricsson blue cell phone for $100.Compared to Rogers,FIDO's service is better and you do not need to sign any contract.Moreover,you can use it in major cities of North America,say N.Y.Most cell phone service providers in Ottawa is providing customers different packages which cost you from $30-$60/month.If you are lucky to register when there is a promotion package available,you can even pay less than regular ones.
However,there is one concern that FIDO requires credit card when you apply.And if your credibility doesn't meet their minimum requirement,your application will probably be refused.Generally,if you have used credit card for over 3 months and don't have any bad record,there should not be a problem.Otherwise,you'd better to apply to other companies that don't need your credit card record though I am not clear about that kind of procedure.
Hope it will help you.Good luck.