I subscribe to eMusic at $9.99/month for 40 songs (less than 25 cents each). The files are 256k MP3 with no DRM. Once you have paid for the download, you can download the file as many times as you want. The (relative) high quality of the files and the lack of DRM mean that this is the only online service I choose to give my money to.
No major label content here, so if you are looking for Black Eyed Peas or even U2, go elsewhere. I always find forty songs and have a few more albums on my Saved for Later list. My recent downloads have been Calexico Garden Ruin, Josh Rouse Subtitulo, and John Coltrane/Thelonius Monk.
My current project is available on iTunes and other download sites for $0.99 each, but not on eMusic, but I still like them.