Is this legal? Can they really code in a different price based on the end user's profile? That sounds super shady to me. I know there have long been suspicions

Is this legal? Can they really code in a different price based on the end user's profile? That sounds super shady to me. I know there have long been suspicions that Amazon does this but I thought all of them turned to be false. If a company as big as Orbitz is doing it, are there other companies that do it too? I am surprised this has not come out sooner.