Recently a printer cartridge was sold to a family member “on sale” (ie $3 off the marked price of $28) . Upon arriving home it was discovered that the price tag of $28 had been stuck over the original price tag of $22! And I’ve heard of this before, with watches and makeup. So it’s worth your while to take 5 seconds to check that you actually are getting a sale price and not a marked up price.
The other point for this week is to check if an item is scanned at the sale price. Again, this happens often at supermarkets where grocery items are on sale but the change hasn’t been made at the register yet. Don’t become fanatical but do check those prices.