This is a bit off topic, but I've loved using Amie Street for the last year or so. They've got some of my fav bands on there (GBV, Yo La Tengo, Preston School of Industry,etc), even if they might not carry every single album. And I've found a lot of cool new stuff, too. They have this pricing scale based on popularity so that the more obscure a song/album, the cheaper it is. They seem to have relationships with some better labels (Matador, Delicious Vinyl, Beggars Banquet, 4AD, to name a few). But I'm not sure how they partner with artists.