I stayed in downtown Montreal at a Delta hotel(Delta Centre-Ville) for $60USD/night.
If you haven't used priceline before, be warned, you have to pay upfront and you don't know which hotel or if any will accept your bid.
All you do is choose a region, like downtown montreal etc, they show you on a map where it could be. and you could be booked at any hotel within that region. You do not get to choose/accept the hotel you are automatically booked there.
You choose the location, star rating and a few other restrictions, but other than that they can book you at any hotel they have agreements with. or your bid is declined, then you just increase your bid.