Hi,
Montreal has actually traditionally been one of the cheapest places in North America. It is still possible to find bachelor apartments for $400 per month and pretty decent parts of the city, if you know where to look. That being said, if you do not have a job yet, any place is going to be expensive.
From personal experience, I think Montreal is very reasonable. A one month pass for the metro is $70, you pay roughly $500 per year for the public prescription plan if you do not have private insurance, tuition is the lowest in Canada, and rents are still affordable. You can also take French classes for free here and although taxes are the highest in Canada, if you find yourself in any kind of a special situation-like renovating a condo, spouse not working, newborn child, for example-you are entitled to many tax breaks.
I would only caution you about two things: The job market is very competitive here, and you will need to commit to learning French if you want be upwardly mobile. If you don't mind those two things, Montreal is a great place to live with many opportunities to become part of the community.
P.d.R.