Over the weekend I went out for grocery shopping as I normally do. The local Walmart had a nice big sign for the TrueTaste milk, on sale for $3.97 for the 3pouch bag. Oh, guess that Nelsion is putting on sale to try and switch people from regular pasteurized to their filtered milk. it does taste different so why not.
What you don't realize is that bag has written in as small as you can get away with that it's now 3L of milk rather than 4L. So the price drop really isn't a drop at all, but actually an increase as you are getting 1/4 less milk for the lower price.
Now that explains why we went through a whole bag of milk this weekend where usually we only get through 2/3rds.
That's why you shouldn't shop for groceries based on price.
You shop based on price per volume.
It might be irrelevant if the 3L costs less PER litre than the 4L option.
Take a look at no name brand cereal as another example. Many of these once touted as generic, cheaper options to the brand name cereals actually cost the same per volume. The no name brand cereals were sold in larger quantity boxes which made them 'look' like it was a better deal.
