Google Music has an Artists section that takes you through a fairly simple process for getting your songs on the site. Google takes 30% of the sales, you’re paid monthly, there’s a one-time setup fee of $25, you can upload unlimited tracks and unlimited albums and make unlimited changes and there is no annual fee.
You get an Artist page, to which you can link your YouTube account so you can sell directly from YouTube. Finally, a really nice feature of Google Music is that when someone buys music through it, they can give their followers on Google+ one free listen accompanied with a buy button. Found at YouTube from googlemusic.