I am recalling from my memory, but I believe the inflight catalogue said if you spend CAD $100 you receive 250 miles and if you spend CAD $200 you receive 500 miles.
As for duty free pricing.......my personal opinion is that the term "duty free" translates into "rip off" in over 80 languages. With one or two notably exceptions, I would never buy anything from a duty free store/aircraft.
[This message has been edited by Carioca Canuck (edited 10-20-2001).]