Going to Montreal for the first time in June...?

You might want to look into the HI-Montreal (Hostelling International). They have shared dorms from $26/night, and private rooms from $86 ($75 for HI members). That's about the cheapest accommodations you'll find in Montreal, but it's still clean and has great character. It's literally two minutes from Crescent Street (and Sainte-Catherine), which is the hub of Montreal's night life.