For those doing the western promo for booking YYC-YVR or YYC-YEG city pairs (5 Roundtrips gets you a ticket to the sun), make sure you are not choosing the only marginally cheaper N class fare. L fare is only about $10 more but is eligible for the promo.
The link from the promo takes you to the booking engine that allows you to book N class fares--read the fine print. You can get L fares with some difficulty for the times you want but it keeps trying to shove N fares in your face. You will not get your free tickets if you go that route though.