Sony wouldn't have the right to sell your song. Though anyone could copy it to and from anyone, only the original creator is allowed to charge for it. So Sony couldn't make a buck on your music, only you could. You could simply charge for gigs, or set up a donation account: if others want your music, plead for them to donate some money. This is how it could be done(and has been done, before people started selling records). If they like it, and possibly want to support future production, you would encourage them to chip in.