In my community (in Canada) the local Safeway store will give the
customer an item for free if the scanned price (during checkout) is
more than the posted price of the item (providing the customer notices).

Recently I purchased an item at a different retailer and was charged
more than the posted price. I did not notice the overcharge until I
had left the store and after returning to the store and waiting in
line for 20 minutes (at customer "service?"), all they would do is
refund the price difference between the charged and posted price
(which was about a dollar).

From a legal standpoint, what is the retailers obligation when they
charge more than the posted price for an item? Does Safeway just have
this policy to keep customers happy?

For comparison, here in the United Kingdom many supermarkets have a
similar policy, however the law does not require it. It is a goodwill
gesture to stop customers complaining to Trading Standards, because it
is a criminal offence to display a false or misleading price
indication: Sale of Goods Act (Price Marking Order) 1999. The Consumer
Protection Act 1987 makes it a criminal offence to give consumers a
misleading price indication about goods, services, accommodation
(including the sale of new homes) or facilities.

Failure to comply with the legislation could result in prosecution and
the Courts may impose a fine up to GBP 5000. In some cases, the fine
may be an unlimited amount.

Owain

The same is true in the United States. It's up to each individual
store to set its own policies on how it handles overcharging.