I've been doing this for a dozen years MCO-YUL, and out of my base, either JFK or DTW. US carrier to Canada is free. Canadian carrier will charge you the departure taxes for whatever airport you're going out of. For instance, Air Canada charges 4 bucks MCO-YUL, but coming back is the kicker. $58 now to j/s out of YUL on Air Canada, $37 or so nonrev fee for DL. If you j/s DL, they actually charge MORE! Like $44 or so.

So, it depends on which way, and what carrier, and the airport departure taxes. YUL used to be only $15, and you could bypass their little desk while in uniform. But now, it's all incorporated into the ticket. AC's nonrev line is 800-413-1113 #1 for English, #5 for reciprocol j/s desk.

Bonne Chance!!