The following works in the USA, I haven't yet tested it yet in Canada:
WALMART:
Look for the shelf prices that end in 1 cent. Example: $19.31
That means that this particular product has been reduced, but not advertised. Apparently WALMART doesn't charge 1 penny on their pricing of any other products. Just wander the isles looking at the price tags, until you find one with the 1 cent ending. Then looksat the product to see if it is something you want. This can save you lots of money and you can get lots of products you're wanting.
COSTCO:
Look for shelf prices ending in 97 cents. Example $19.97
This type of pricing for Costco means they are selling for less than cost.
