I'll admit that I tend to implicitly trust that the larger boxes on the shelves contain more. I haven't checked the price-per-unit in a bit. Granted, my closest grocery is not a WalMart and I'm typically purchasing mass-produced sundries. Basically, the "Family Size" of Cheez-its is the same at any store.
One thing I have noticed is that 5lb bags of flour/sugar haven't been standard in a hot minute.
FWIW in Switzerland (and surely other places too) you have on the price tag also the price per 100g (or ml or whatever) so you can quickly compare without bothering much with basic maths. Same for online shopping.
One thing I have noticed is that 5lb bags of flour/sugar haven't been standard in a hot minute.