Bristol Posse
Okey Dokey
Realistically, performances probably drive sales. If you can't/won't perform live, I'd think it'd be very difficult to otherwise effectively publicize your music in a way that will cause people to want to buy it. If you perform, and people like what they hear, they may buy it if you let them know how to. I doubt that many people surf the web looking for sites where they can click on links to songs by artists they've never heard of, just in case they might like their material.
You might be surprised! there are several indie music sites for who that is the entire raison d'etre emusic is kind of going that way