My husband and I have recently gotten into vinyl so we've been making an effort to check out local shops wherever we go. Cheap Thrills was a fantastic surprise for us. After reading other Yelp reviews on various record shops in Montreal, we knew this was the one for us. Don't be fooled by its appearance--they have SUCH an impressive supply. We didn't go in looking for anything specific, but we left with a full bag of music. It's organized really well and is easy to search. The staff wasn't really into talking music with us and weren't all that inviting, but we left with great records nonetheless. They were also pretty fair on their pricing.
Also: don't be fooled by the somewhat confusing entrance. This shop is on the second floor. Walk up the stairs from the sidewalk and then up two more flights of stairs once you're inside the building.