If you're a fan of Blizzard's music, you can now acquire the Reaper of Souls soundtrack through iTunes. You can purchase the album for $9.99 or individual tracks for $1.29 each. The Reaper of Souls music page on Blizzard's website includes 30 second samples of each track as well as composers' notes.
If you find yourself interested in multiple tracks, we suggest just going in for the album -- there are 22 total tracks, adding up to a significant cost difference. $9.99 or $28.38? The choice is yours!