Each of the pieces on this site are available under different licenses. With Credit Given (Creative Commons) - Free!
By default, they are licensed under Creative Commons: By Attribution 3.0. To use this license, simply attribute the music in your piece (website, film, phone system, etc.) as is reasonable to the medium. [more info on attribution].
There is no cost to use music under the Creative Commons License.
If more information is needed, please be specific what you need from me.