According to the law, it only matters if you're legal in the province that you're entering. You can bring small amounts of booze, but I believe it's only like 6 or 12 beers, two bottles of wine or 40oz bottle of spirits. After that, you have to pay duty and at that point, just buy it in Quebec, which has the cheapest hooch in Canada anyway. I wouldn't even bother, you won't save much money and you're inviting a problem. All it takes is one dick at the border to really delay your trip.