If by this you mean that standard supply-demand economics can't model price discrimination, which is what's going on here, that's not correct. See, for example, Chapter 10 of David Friedman's Price Theory, where he models price discrimination using supply and demand curves just fine. In terms of this kind of analysis, price discrimination is a way for sellers to try to transfer as much as possible of what would otherwise be consumer surplus, to themselves.

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WalterBright 5 hours ago | parent [-]

And the buyer tries to pay as little as possible. Negotiating is a skill well worth learning (lots of books on it).

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9dev 3 hours ago | parent [-]

This discussion is perverse. Negotiations require leverage, which the average grocery buyer in the USA does not have. As a society we don't benefit from min-maxing absolutely every opportunity.

	▲	WalterBright 2 hours ago \| parent [-]
		The leverage is walking away and patronizing another store or online grocery service. > As a society we don't benefit from min-maxing absolutely every opportunity. Negotiation does take some effort, sure. But then again, you get to decide if it is worth the effort - Supply & Demand again is in play. But you might argue "this is the only grocery store nearby!" I grew up in a small town. My mom never bought food in town. We'd drive 30 miles to the Army Base and shop at the Base PX. She'd buy 2 weeks worth of groceries at a time, because it was cheaper in the PX. My parents lived through the Depression, and were both very frugal.