"best buy sales ad" is a broad, commonly searched term, and what actually qualifies as a genuine deal in Canada varies significantly by category and by retailer. The most consistent signal of a real discount is a price that's clearly lower than what the same retailer was charging in the weeks immediately before, rather than a price simply labelled as reduced.
Retailers such as Best Buy in Canada publish their current promotions through a regularly updated weekly catalogue, which remains the most direct source for what's genuinely discounted that week, rather than relying on older listings that may have expired.
Browsing the current catalogue listings for Canada is generally the fastest way to compare active offers across multiple retailers at once.