Unit pricing -- specifying the cost of goods in terms of a single consistent measure -- has been a legal requirement in Australia since December 2009, and the ACCC has promised to crack down on stores which don't use it. However, there do still seem to be problems when it comes to specials.
Regular Lifehacker commenter poedgirl points out that in recent weeks, Coles appears to have been inconsistent in its pricing approach on specials. In the attached shot, the unit price for Coke has been specified for the regular price ($1.33 per litre), but not for the '3 for $5' special (which would work out at around $0.84 per litre). Missing the unit price for the special actually undersells the deal.
Arguably, if one price is going to be missing, it's better for it to be the special: that way, the unit price for a single bottle remains accurate, and someone who takes up the special gets a better deal, not a worse one. But offering both prices would ultimately be more useful for consumers -- and, it must be said, more persuasive.
Unit pricing is a great idea but does have some obvious flaws in the current implementation. For instance, the units used vary for different categories (per 100g for some, but per kg for others), and there's often even variation in a given product category. Nonetheless, it's still something that makes shopping easier, and we're keen to see it used properly. Have you spotted similar unit pricing issues in your local supermarket? Tell us in the comments. Thanks poedgirl!