IMO it should be illegal to charge 2 fungible customers with materially different prices.

Anecdote: Once upon a time I was going to see a rental that was listed with a certain price, so I called and booked a showing. The day the showing came the price had risen something absurd like 30% ... The agent smugly told me "That was Monday's price" ... I told him I do not do business with people who bait and switch, and left.