Not sure if this is against the rules, if it is, feel free to close it and I'm sorry
You can get a free Pid cd-key for steam, legit.
You must like this page; (you need an account to see links) and like the 2 pages, then you'll see the key on your screen and you can activate it via Steam.
I used a fake Facebook account, cause you never know, and after that I just removed my likes again