It may be one of the best kept shopping secrets. Shoppers, like Susie Parker say she saves close to $100 a year just by watching the register.

"It's about paying attention to the price on the shelf and paying attention when you get to the register," says Parker.

It's called the scanner price accuracy code, a national strategy retailers can choose to adopt.

If a business opts into the program they are obligated to give the shopper discounts if an item is scanned wrong.

Safeway follows the scanner price accuracy code. They say if a product less than $10 is scanned incorrectly you will get it for free. If the item is above that amount, you get $10 off.

"People should become more informed about it," says John Graham of Canada Safeway Ltd. "People have an inherent faith that prices are accurate."

Many big chains like Wal-mart, Home Depot and Shopper's Drug Mart have adopted the code. Some even post information about it at check-out yet many shoppers have no idea it exists.

Retailers must voluntarily participate in the scanner price accuracy code. The Retail Council of Canada's education campaign aims at educating its members about the code – to avoid confusion at the till when it's brought up to staff.

More information on scanner price accuracy code is available on the Retail Council of Canada's website.