I never thought I'd write a post about such a mundane topic as peanut butter, but here I am, doing just that.

Where it comes to buying peanut butter (a staple food for me), I'm one of those cheapskates who couldn't care less about brand loyalty; I buy whatever is on sale. Jif, Skippy, Peter Pan, the store brands -- they're all the same to me. I just buy the cheapest I see on sale, based on the lowest unit price per pound.

While I hadn't paid too much attention to container sizes, I couldn't help noticing that I almost always buy the small (18 oz.) jars because they are cheaper per pound than the larger sizes. Robotic linear thinker that I am in these situations, I simply contented myself to buying lots of small jars. Sure, I go through them faster, but so what? On those rare occasions when the unit sale price is cheaper for a larger jar, I'm happier to have it, because it will last longer.

What jolted me into writing this post was a conversation in which I was told emphatically (by someone with expertise about such things) that the smaller sizes "always" cost more per pound. Not being one to argue, I thought that maybe I'd been wrong, and perhaps I was being swindled without realizing it. (After all, I hadn't paid much attention.) The conversation triggered a childhood memory in which I distinctly recall being told (by a female second grade teacher, I think) that it is "always" cheaper to buy food in larger sizes, because the more quantity you buy, the lower the price per pound.

Now I had to find out.

So the next time I went to the store I did two things. First, I checked the prices very carefully, and sure enough, the cheapest unit price was $1.60 per pound for the 18 oz. size of the store brand. There was a larger (28 oz.) size also on sale, but it was a whopping $1.92 per pound! That's substantially more.

One of the cashiers has worked at my local supermarket for a long time, and I consider him a friend. He is a highly intelligent, friendly, and no b.s. kind of guy, which means that he'd never be made the store manager even though he'd do a far better job than anyone else. I knew he'd give me the true scoop.

I was pretty sure I'd already figured out what was going on: more people want the larger size, because it lasts longer, and because they think they're saving money. Sure enough, the cashier confirmed my suspicions.

"They know that hardly anyone checks the unit price per pound," he said.

He also told me that it was the same deal with cream cheese. People just assume the larger size is cheaper per pound.

Is there anything dishonest about this?

Frankly, I don't think there is. They are clearly displaying the unit price per pound, and I have been buying the smaller, cheaper sizes without giving it a second thought. That other people don't bother to read the prices isn't the store's fault. Besides, many of them would buy the larger size anyway, even if they knew it cost more, because it's more convenient.

Parenthetically, and at the risk of sounding crazy, why am I thinking that many of these people (who apparently don't mind spending an extra 30 cents per pound for peanut butter when they don't have to) will go out of their way to save a nickel a gallon for gas? Are they crazy, or is it just me?

Sheesh, I just found a consumer warning about this very issue:

Be careful of the bulk size boondoggle. While buying a larger size is frequently cheaper it isn't always. In fact retailers sometimes charge a higher unit price for the economy size. Not only in grocery sections can this occur, but also in health and beauty aisles as well. Again, the unit cost price is your financial friend in revealing what you are really paying.

For many years I lived in a crummy Berkeley neighborhood which had a lot of low income, Section 8 apartment buildings, drive-by shootings, that sort of thing. There was a Safeway a few blocks away and a local liquor store and "convenience" store which sold groceries at prices I thought laughable. It never ceased to amaze me how able bodied adults would prefer to spend a lot more money on groceries at ripoff prices rather than walk an extra two blocks to Safeway. They weren't being ripped off, though. They were paying more for the convenience. I never felt sorry for them at all, as I considered them fully capable of making choices.

Others used to tell me that the corner store was "taking advantage" of "the poor." Were they? What advantage was being taken? If I were wiped out financially and had to get by on food stamps or something, I'd buy rice, beans, powdered milk and tortillas for whatever were the lowest prices I could find, and I'd have food for the month. If someone else wants to buy grape soda and cheese puffs at $4.95 a bag, why is he being taken advantage of any more than I am? Don't we both have the same ability to select which items to buy? Unless the person is mentally retarded or something, I've never understood the "taking advantage" argument. Sounds like "exploitation" (another meaningless word). Or insisting that "the poor" have a "right" to live in Manhattan at an "affordable rent."

Then there's "economic apartheid." This ill-defined concept (dreamed up by Harvard Ph.Ds who specialize in undefined undefinables) involves things like "forcing" poor people to things like use check cashing centers instead of banks, and furniture rental stores instead of thrift stores. I mean, really, if you can't afford a new couch or a TV, there are plenty of used ones for sale cheap. Why would anyone pay more to rent a new item for one month than it costs to buy it used?

Beats me. But then, I'd never buy a new car either. That's because if I did buy a new car, it would substantially decrease in value as soon as I drove it off the lot. Yet as I say this, I recognize that many people love to buy new cars. They have every right to pay more for what they like, and it's good for the economy.

It's just that if I have to hear that they've been taken advantage of or something, I get worried that we're all being forced into a vast national kindergarten.

That's a fate worse than repeating the second grade.

MORE: My thanks to Charles Hill for the link, and his wise observation that you can't legislate thrift.

And Arnold Kling (via Glenn Reynolds) has a must read article in TCS on libertarianism and poverty.