I just found out that every few months Apple releases a free “new music sampler” album via iTunes. I knew about the free weekly single download, but had never heard of the free album. I found two that are still available. Click the links below to launch iTunes and go to the albums.
http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewAlbum?playlistId=39887273
http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewAlbum?playlistId=39795974
I read a comment over at OSX Hints that said if you google iTunes New Music Sampler, you can usually find them.