Had a question in the a comments asking about SCOP – Scanning Code Of Practice. Thought it might be helpful to make a post on it.
If an item scans in higher then the advertised price the customer is entitled to receive the item free (up to $10). The price must be corrected to the advertised price before the $10 discount. This only applies to 1 item if you are buying more then one of the same item, the rest are just price adjusted to the correct price.
If the scanned price of a non-price ticketed item is higher than the shelf price or any other displayed price, the customer is entitled to receive the item free, up to a $10 maximum. When the item has a price tagged, the lowest price applies. When identical items are incorrectly priced, the second one will be sold at the correct price.
IMPORTANT: Stores do not have to participate in the Scanning Code of Practice – it is optional. But a lot of the bigger chain stores do (except Zellers).
Also, many stores won’t mention SCOP even if you catch a price error – you usually have to bring it to their attention and ask for you free item/$10 discount.
Here is some more information, including a list of the participating stores.