I found some free albums over at Amazon and they seem to come in two flavors. First is the one I prefer, which is newer artist trying to get their name out. Second is sampler albums which either record companies trying to get their artist out or music festivals advertising for next year. On the Artist side I did find sweet little album in what I like to think of as the pop/grunge sound Quarterfly - Addiction Sampler. This is the sound Creed started and Train perfected, Quarterfly does it well. Also found a thoughtful hip hop/ rap album from Element B. Fresh. Born Fresh is the name of the album and this is not your aggrandize yourself music, instead it is a more mature sound and look at life's troubles. I like these better because it is one band and so the sound is more consistent. Sampler albums on the other hand have a number of bands on them, mostly unknown although you can get lucky like this Bloodshot Best of 2010 Sampler which has both Townes Van Zandt and Graham Parker on it. Most though are more like this CMJ 2009: The Bands, the City, The Music Vol 3 where the music is so scatter shot that you are better off taking the time to single out the songs you want. Then comes the genre samplers like Tad's Record Dance hall & Reggae Top Ten where the added question of whether you like the genre in question gets in the mix.
The good news, the music is free, the bad news, listen first to make sure you can stand it.