If you take charging higher grocery prices for richer people to its furthest point, you could end up with a system where every item costs Y% of their assets and the utility of a dollar is reduced the more you have. In effect, this would eliminate the relative value of having more money. For example, eggs could be priced at 0.02% of total assets, which means a poorer person with $2000 pays 40 cents, and a richer person with $1M pays $200.

Now, would this go to its furthest point? Probably not, but it has the same, but smaller, effect of reducing the utility of money for richer people.

In some scenarios, this actually might make sense. For example, in Finland, they use the day fine system where traffic ticket fines are based on the violator's daily disposable income. It's useful because this is a scenario where you want the punishment to feel equivalent to all income levels.

For groceries, I don't think this should apply, because I think we would not want the act of purchasing food to equally punish all levels of wealth.

This really becomes a philosophical discussion of defining price gouging and immoral market techniques. Some are clearly gouging, such as charging 2x plane fares for someone who has to fly to a funeral, or tripling the price of supplies after a natural disaster. Some are less clear.

How can price discovery work if everyone’s price is different? What downward pressure would even exist on surveillance-derived prices besides resale black markets? Societally, do we really want to further monetize the expansion of the mass surveillance state?

> If I'm selling to the wealthiest zip code, where the median house price is over $10M, should I be disallowed to charge higher prices?

I think so, because perhaps your costs to distribute those products is more too. But what I don't think you should be able to do is say, well your house was $50mm and your house was $1mm so you pay much more. Or you're wearing Air Force Ones so maybe your price is just a little more wink wink. It's a bit like hyper-targeted advertising versus general advertising.

> If I'm posting something for sale on Craigslist, and I don't put a price, is it OK if I quote different prices to different people who text me?

I think so as well. I don't see a problem with this - you don't know anything (maybe besides a green/blue text) anything about the buyer, how much they make, &c.

Not comparable. The markets can still charge wherever they want, but it needs to be priced per item and not per customer. In your house counterexample, you could set whatever list price you want.

> If I'm selling to the wealthiest zip code, where the median house price is over $10M, should I be disallowed to charge higher prices?

Yes, you should be disallowed. Otherwise every online store will upcharge you based on IP. There can be exceptions for small businesses or individuals, but that's it.

> airlines charge more if you're too large to fit your seat

I don't think this is a good example, because you're literally using more of the product that's being sold. I get where you're coming from but this one doesn't seem to really reinforce the point you are trying to make. It's like selling by weight or something if you wanted to compare it to groceries.

There is charging more because your costs are higher (most of your examples), then there is charging more because of opportunism. Insurance is customized because the costs are higher. That's fine.

Taking advantage of your personal circumstances that is unrelated to cost to charge you more--especially when it is hidden from you--is what is bad and should be illegal.