Quantity pricing math - what am I missing?

[Music Lover]

My Father had a local delicatessen. He had different prices for different people, lol. But, I remember asking him why would people buy the tiny jar of mayo when for maybe 20 cents more they could get the quart size. He said that for one thing they might keep that jar for 6 months and not want a quart to sit in the fridge for 2 years, and second they didnt have the other 20 cents.

Obviously, I can afford mayo, but waste bothers me...even though I'm saving money it bugs me to buy more than I will use before it goes bad. I solve the mayo dilemma by buying the large container from Costco for my parents who use a lot of it...I just scoop out 10% - 15% of it for my small container.

 

[CaptTom]

...I said it's the number in the orange field of the price label. She said she never noticed that and was unsure what unit pricing was.
We all have our weak spots.

All of our grocery stores here have a "price per 100mg or per 100 ml" (about 3.5 ounces) for most products, so it's relatively simple to determine which size is the better price.

One thing I did notice though in stores here is that most of the time the retailer did some math for you: apart from the total price you also get a price per kilo/liter (in small print). Super convenient but frankly I don't get it why they do it.

Be aware that the math-challenged also calculate those unit price numbers in the small print, or in orange, or whatever.

Sometimes their math is flat-out wrong. Other times they are comparing different units ("each" vs. "ounce" or whatever.)

I always do the math in my head before deciding which size to buy, or whether to buy the store brand or name brand. A hold-over from when I was poor, I guess. It's not really that difficult if you use round numbers. If you need a calculator to get the exact price difference, it's probably close enough not to worry about.