That's actually really interesting and I had no idea that was the case. In a supermarket, would such a list be in the isle next to the food? Or would it just be available from management or something like that?
You have a price per unit. Say a 0.5l bottle of beer costs 0.78 EUR and then you have the price per 100ml or 1l below it (1l = 1.56 EUR). It's marginally useful if you compare the price of rice to the price of Coca Cola but it's really useful if you want to know what's cheaper: Buying a package of 6 1.5l bottles of Coke or buying a crate with 18 0.33l bottles.
I'm a sucker for saving pennies ;)
Item A: $3, $6/pound
Item B: $4, $0.30/oz
Here
[1] http://2.bp.blogspot.com/-i80uxvW1SnA/Tp3zocKih4I/AAAAAAAAAJ...
[2] http://www.freshfrom77.com/wp-content/uploads/tesco-multi-bu...
Usually, they just tell you on the shelf's price tag:
Bigger Font: 1.50€/£ Smaller Font: 0.75€/p per 100g/100ml etc.
That way, you can see that sometimes it makes sense to buy 2x 400ml ketchup (just as an example where I had it recently) instead of 1x 800ml, simply because 2x 400ml is actually cheaper.
> That way, you can see that sometimes it makes sense to buy 2x 400ml ketchup (just as an example where I had it recently) instead of 1x 800ml, simply because 2x 400ml is actually cheaper.
That applies to plenty of dastardly stuff too e.g. the big 3-5kg pots of Nutella you see around Christmas? The unit price is often twice that of the standard 750g pot.
Brand A, Orange Juice, 1L. 19.90 (Price per Litre: 19.90) Brand B, Orange Juice, 2L. 30.00 (Price per Litre: 15.00)
This is simply to spare the consumer of doing the math themselves, which can turn out to be quite tricky in some cases (although not in my example:)
Update: According to NIST, 21 of the 54 US states and territories have some form of unit pricing law.
It's on the price tag/label, there's the product price and the unit price (except bulk which only have unit prices).
Only if you swim between the isles. I believe you meant aisles.