The campaign is "Pay What You Want" meaning there's only the $1 pledge level, but you can pay anything more than that if you wish.
From the campaign:
Tabletop Soundtracks: Elemental Adventure Path is a new collection of tabletop gaming soundscapes, sound effects and songs to set the mood and inspire creative gaming sessions for fantasy themed games like Dungeons & Dragons, Pathfinder, Game of Thrones, Call of Cthulhu or miniatures games like Warhammer, Warmachine, Descent, Malifaux etc. (no endorsement implied, these are just examples of games that might be aurally enhanced by this project).
To celebrate the upcoming release of the new Adventure Path for the world's oldest fantasy roleplaying game, the focus of this collection is Elemental magic, monsters and environments! That means lots of fire, water, air and earth effects! Currently the package includes 100 TRACKS for THREE HOURS of audio, but can be extended beyond that with Stretch Goals