Where is Alien: Isolation free?

I've been hearing a lot about Alien: Isolation lately and its tense, survival horror gameplay. It seems like a game that would be perfect for a rainy day or a late night session. But the question I'm really wondering about is, where can I find Alien: Isolation for free? I understand that most games require a purchase, but I've seen mentions of free versions or promotions. Are there any legitimate ways to play Alien: Isolation without paying the full price? Or are there any trials or demos available that could give me a taste of the game before I make a purchase? I'd really appreciate any insights you have on this matter.