I sell between 15 and 20 boxes a week; I'm in an urban location so got lots of neighbours to sell to.
One thing to bear to in mind is that I noticed you mentioned 'Free Range'. Best to steer clear of this tag unless you've got official free range status. I advertise mine as 'Farm Fresh' and because I'm selling small scale, I'm happy to chat with all my customers etc about the chickens, living conditions etc.