I bought mine on Kijiji. I've seen a couple pop up there over the years but they're always obscurely listed in the paintball section because Kijiji doesn't allow firearms, airguns, airsoft, etc. Your best bet would probably be here or another firearms/airgun related classified site or forum. Years ago I think there were some Canadian sites involved with biathlon, smallbore and competitive air rifle shooting that sold them but I'd imagine they're long sold out.
I assume you're buying this for your son or daughter? If so maybe try talking to some of the officers in their unit; especially the ones involved in the marksmanship program. Oftentimes they will have bought them for their kids who then age out. Also try Cadet related Facebook groups. Don't make it a WTB post because it will probably be taken down; but ask about where to find one and you might get people messaging you.