Are you sure? This link shows it as free: https://www.amazon.com/Star-Wars-Knights-Old-Republic/dp/B017UYFNYQ/
Edit: it looks like Amazon Underground was cancelled recently and it doesn't work anymore.
That didn't work. Amazon has some apps labeled "Actually Free" try this link Get Star Wars: Knights of the Old Republic from the Amazon Appstore. Check it out - https://www.amazon.com/dp/B017UYFNYQ/ref=apps_sf_sta
They aren't accepting new apps for it but the old ones that were already on it are still free.
I checked this morning and it still appears to be free: https://www.amazon.com/Star-Wars-Knights-Old-Republic/dp/B017UYFNYQ/
Edit: nevermind it looks like Amazon Underground was cancelled recently.
here's a bunch of top quality games on Amazon Underground, better hurry if you want any of em:
these links should all be correct, for the 100% free Amazon Underground versions of the apps. let me know if anything's wrong
added from the comments here:
if anyone likes Hidden Object games, there are a bunch from:
you can go here to search for others, make sure the search bar says Underground Apps before you search.
No problem! If you have a Kindle Fire Tablet, it's actually free on amazon right now or if you run the amazon app store! That's how I'm playing it. https://www.amazon.com/Star-Wars-Knights-Old-Republic/dp/B017UYFNYQ