Last night, I went to Dominion on Stavanger to pick up a few items, one of them being orange juice. They had 2.63L plastic bottles of Tropicana on special, but I try not to buy plastic bottles if I can avoid it. The next available size was a Minute Maid concentrated juice in a 1.75L carton, priced at $3.99 -- a per-100ml price of $0.28. Right next to it was the PC-branded orange juice in the same size container, also priced at $3.99. All things being equal, I generally go for the 'not from concentrate' option, and while picking up my carton of PC juice, I noticed that the per-100ml price on the shelf label for this product was listed as $0.21.
Math and I are not the best of friends, but I quickly figured out that one of the prices had to be wrong. Turns out I was wrong. The PC juice per-unit price was correct indeed, based on the shelf label information, which listed the carton as being 1.83L. Looks like the grocery shrink ray has struck again! There was no one available at customer service to speak with, but it really made me think about how important it is to read labels, compare prices and generally be aware that shelf prices may not always be what they seem.