They are naming different prices for different people.
You walk into a bar and the guy in front of you orders a beer for $5. Looks good, so you order the same thing. The bartender says, "For you it's $10." Do you feel fairly treated?
You walk into a bar and the guy in front of you orders a beer for $5. Looks good, so you order the same thing. The bartender says, "For you it's $10." Do you feel fairly treated?
Moreover next to the price there's a disclaimer that the "Price is subject to change".
To me it seems that they're just running an experiment to determine what's the price they should put to the service, which seems smart and correct.
It's the intent I guess. The bartender story seems to imply a bad reason for the discrepancy (some type of unfair discrimination), while in this case it's to find out if you can charge more to eg capture back more of the value people are getting from you. Which doesn't seem so bad.
Then there are tests that would be hard to run even on different days, like doubling your nominal price and splashing a "today only 50% off" or "buy one get one free" offer.
Real-world price testing is so much harder to pull off, it isn't as common, which is part of the reason web A/B tests seem jarring when the curtain is pulled back.