I’m pretty sure that the Montreal paper tickets are non-refillable but can “contain” multiple rides or a pass (weekend, weekly, etc) if you buy them together.

I’m pretty sure that the Montreal paper tickets are non-refillable but can “contain” multiple rides or a pass (weekend, weekly, etc) if you buy them together. I’d bet a lot of them are sold at the airport: the fare to downtown comes with a 24-hr pass for other buses and metros.