I would have said just go to the contest sponsor (http://www.gungear.ca/camping/case-of-12-mre?rq=meals) but unfortunately they're sold out at the moment.
Try Costco. I know for sure you can get them online if they're not in the store. Different brand from what's being offered in this contest though.
http://www.costco.ca/7-day-Emergency...100036141.html
Or you can try Meal Kit Supply (http://www.mealkitsupply.com/) which makes the MREs that Costco sells.
Hope this helps.
Edit: the ones that Gun Gear sells are cheaper than the Meal Kit Supply MREs as well. If they weren't sold out, I'd likely pick up a case or two.