For a minimum of $1, you get the soundtracks for
Monaco
Fez
FTL
Gunpoint
Leisure Suit Larry: Reloaded
World of Goo (Also available for free from developer's site)
For $10, you get soundtracks for
Me and My Dinosaur 2
Frog Fractions
The Forge
Super Panda Adventures
Drox Operative
Hero of Many
Marble Time
Little Inferno (Also available for free from developer's site)
As well as
Anoydne soundtrack and remixes
FZ: Side F and Side Z (Fez soundtrack remix)
Monaco: The Gentleman's Private Collection (Monaco soundtrack cover)
http://www.gamemusicbundle.com/