Located in the Marche Bonsecours building, the Boutique des Metiers d'Art was probably my favorite shop. It's a consignment boutique for the Quebec artists' guild and they carry everything from paintings to sculpture to clothing to (my favorite!) jewelry. Out of all the places I went in Montreal, this was probably the best place I found to get locally made (and I mean locally as in Montreal) products that aren't the cheaply made things you find in most local fairs. Most of it has quality and is unique and as such it's not cheap, but it is definitely below gallery pricing. They'll also ship your purchase if you need them to for an extra fee.
It's in Old Montreal and as such it's not easy to get to. You can take the Metro to Champ-du-Mars, but it's still a 5-10 minute hike up and over the natural levy.
The Boutique des Metiers d'Art which is really worth the visit if you are looking for a local art worthy of art galleries but don't want to pay gallery pricing.