The Amazon MP3 Store offers downloads of the Various Artists' NOW That's What I Call Music Vol. 47 MP3 Album for $3.99. That's $13 below the best price we could find for a hard copy of this 20-track, DRM-free pop album, released in August. (iTunes charges $7.99.) It features songs from Justin Timberlake, Bruno Mars, Mariah Carey, and more. Amazon MP3 Downloader is required.