I think he wasn't referring to my comment but to my post where I write: "It’s illegal and can lead to huge potential lawsuit."

> The concept is called "price discrimination".

Not quite - price discrimination is finding a way to take people with more money, and charge them more money. The challenge is, that prices people with less money out of the market - so price discrimination is about finding ways to justify cutting prices for some people while charging more to people who can afford more.

Examples: Student discounts, senior citizen discounts, kid's meals, and matinee prices at movie theaters are all price discrimation. A/B testing prices is... just A/B testing prices.

Though, the wise A/B price-tester does so by offering two different sales - one discounted product, and one more discounted product. This seems to minimize backlash - finding someone else got a better discount doesn't bother people as much as finding out they paid a higher price.

How would that be so? How do you 'believe' a factual thing like this? I can charge one guy 10$ for a pie in my bakery shop, and the next guy 100$ because I don't like his face. There is a narrow set of classes on which it is not allowed to discriminate but all else is fair game.

I'm not claiming to know this of all jurisdictions, there may be specific circumstances in which this does not hold, but these are the exceptions.

Don't car dealerships do this all the time? Or small shops in Chinatown that negotiate for tourist souvenirs? Safeway or CVS cards? Google AdWords? Priceline.com? Employee/corporate discounts? Heck, on my recent trip to the Grand Canyon, my sister and I both checked out the exact same rental car through our respective employers, and it was about $30 cheaper through mine, presumably because my employer gives a better corporate discount than her employer. Really, anything where you negotiate the price will end up with different prices for the same item.

You're thinking that just because people don't do it, it must be illegal. The idea of "one price for identical items" is a pretty recent invention, dating back to the rise of department stores (Woolworth's, Macy's, Sears) at the turn of the 20th century. It's for economic reasons, not legal ones. They found that it was cheaper to forego the extra revenue than it was to hire all the salespeople needed to negotiate each individual purchase. Charge less and make it up in volume. It also has the advantage of fairness and simplicity, which customers tend to like.