Pretty sure you can buy them, and if someone posts a direct link to a free download it would count as piracy and go against the forum rules P. S. Still awesome soundtrack tho
Search them on youtube, then download the video via youtube converter & downloader. Edit: Legal as long as you don't download stuff that's protected by Cr and/or Tm. Which movies/music usually are.
You have them if you buy games on humble bundle or Gog I think, the OST is in deluxe edition, or the artisit is availble and you can buy it online