The Amazon MP3 Store offers downloads of over 800 MP3 albums
each. That's a buck under last month's mention of "greatest hits" albums (though this sale includes several "greatest hits" albums) and puts many titles well below what iTunes charges, which is generally from $9.99. Amazon MP3 downloader is required.
A best bet is
Bon Iver's For Emma, Forever Ago MP3 Album for . That's the lowest price we could find for this 9-track, DRM-free indie-folk album, originally released in February 2008. (GooglePlay offers it for $9.49. iTunes charges $10.)