The El-Al cheap tickets mistake
Halachically speaking, I thought that if a seller made a mistake to the sellers detriment in pricing an item (not that the item’s true value was unknown but a mistake) that the buyer was required to return the item or fulfill the true price if the buyer bought up without knowing it was a mistake.
So how could one who bought a ticket when the wrong price was listed keep the ticket now that it is known the price listing was a mistake?