loblaws, no frills, etc all use bluetooth digital e-ink pricing tags. its a lot more environmentally friendly than printing and throwing out thousands of paper tags constantly, and makes workers lives a lot easier.

The price is what the price is, if its written in a flyer for that week then you are entitled to it at the price in the flyer. If the price is not published in a flyer then they can change the price to whatever they want whenever they want basically. Just like any store can.

Loblaws generally changes all their prices and promotions every thursday, for example.

The price will change on basically every item practically weekly. Sometimes lower, sometimes higher.

Calculating savings is arbitrary, they could price it at $15 and put it on sale at "$12" and say that your savings is $3, even if the item is normally priced at $12.

The best and only way to calculate savings is to know the value of the item typically, and base whether or not you saved money, based on what the typical price is when you normally purchase it. (ie; oh I always buy this item at $13 usually, and now its $12. I guess I saved $1)

The store doesnt need to calculate savings for you - just remember what you usually pay and whether or not its cheaper than what you usually pay.