Last year, my friends stayed at the student residence at Concordia U – the Grey Nuns I think it is called. For around 70 bucks a night the two of them had a private room to themselves, although they did have to share the bathroom (like most college dorms). They’re downtown, close to the subway, and a few blocks away from all the parties on Crescent Street. For the price, they were shocked at how large, clean and not-busy the place was! Whenever I travel in summer, student residences are the places I check first for accommodation. I know the other university residences in Montreal fill up quickly, but Concordia’s is apparently new so nobody knows about it! Hope that helps – they’ve reserved again for this year!
Here’s the website for Concordia: http://vpservices.concordia.ca/summerhousing/
Cheers! Nicolas in MTL