If you don't read the receipt when you get it, youze a phool. There are frequent errors. Each store I go to deals with it differently. In one you have to go to Customer Service, tell them where the price differential is and then they go run around and check it. Sometimes you get the full price back and sometimes you don't. Haven't figured that out yet. Often signage is a problem with prices set out to confuse you as much as possible...like the last time I thought I was getting a deal and had to purchase 2 or more... I wouldn't put too much blame on the poor cashiers who have to stand all the time and are not allowed to have a stool. I know I could not remember the codes and prices for every item in a store, could you?? You have to be a smart shopper and know your rights and when you pick up an item, note the price. I know sometimes we are too tired and the atmosphere in supermarkets is dangerously scary - bright lights, tons of choices, mislabeled signage...and on an on...it's a wonder we get out alive!