"Prisoners" is a surprisingly good soundtrack album, one that's worthy of a purchase. The score is quite dark and somber in tone, but it's a worthwhile listening experience if you like classical or film music.
The film and it's screenplay are so finely tuned, and fortunately the music by Johann Johannsson is also crafted with such precision. The score is never overbearing - it keeps its distance, slowly building the suspense in the background. When the music does come up in a more dramatic fashion, it makes it all the more thrilling.
 The Search Party
 The Candlelight Vigil
 Through Falling Snow