These sites do not offer music for sale. However, if you are looking for a track
of music and don't know the album or the artist, these sites may help you find it:

      

Just use the search engines built into these sites

Music "Streaming" Services
Music streaming services let you listen to music on-demand in the same
way that Youtube lets you watch videos in your internet browser.

   

Last.fm allows you to listen to music for free , like an interactive radio station.
Spotify has a larger library of full tracks but requires you to download the free software.