I found out today much to my delight that if an item in Coles scans at a different price to what it is advertised then you get it free! I just got myself a nice new dressing gown for free! here is a copy of their policy

The Scanning Code of Practice, of which Coles is a voluntary signatory, has been developed to make sure the interests of our customers are protected. The code states that if an item scans at a higher than shelf price, the customer is entitled to the first item free of charge and any subsequent items, with an identical barcode, at the lower shelf price