One of the things Commander Zero often talks about is what he calls 'Hidden Inflation', or what you could refer to as the 'shrinkage' of food/consumables packages at the grocery store, while the price stays the same.
I saw another example of that at the store yesterday. For the life of me, I used to think that canned soda came in 6 packs, 12 packs, and 24 packs. Well...yesterday, I noticed that Safeway was having a sale on Coke Products...$7 for a 20 Pack. Hmmm...I haven't seen a 20 pack before. I've seen the popular 'golf size' 18-packs of beer before, but not a 20-pack.
Have to keep an eye on the bottles...see how long it is before you are buying a 1.75 L at the store instead of a 2 Liter.