Like I said, on Craigslist/Kijiji/etc it is difficult to find such a price, or when it goes online, it disappears very quickly. A price like this can be found by walking around and finding "à louer" signs and calling the number.
But here is one for $650CAD (492.47USD): https://www.kijiji.ca/v-appartement-condo/ville-de-montreal/...
>But that does not mean one can go and get an apartment and pay a rate similar to the one that they have.
But when she dies (probably not far away), the place legally must be rented at the same price (+ inflation of one year), assuming no major renovations are undertaken. And if it get's renovated, the price can only rise to a certain point unless the whole building get's demoed. So someone will get it at about that price, eventually, unless the landlord illegally raises the price (which happens).