Well, there you go. Feed is (say $16) every two weeks. That's $8 a week. You get 12 eggs a week. That means, if you don't eat any of them, you need to charge $8 a dozen to break even!
Of course, that is not counting water, power, grit, oyster shell, supplements, meds, wormers, or housing (original cost and upkeep) or even your time in feeding, care, cleaning, etc. $8 would be a bargan!
But seriously, some areas of the country will pay $5 or $6 a dozen, an around here, people sell theirs for $1.50 a dozen. They are worth whatever anyone will pay you for them. Just remember, if you sell the first ones for $1 a dozen, people will never want to pay you more than that. I'd ask $4 to start, if you don't get any takers, drop it to $3. Offer .50 off if they bring you two egg cartons. They'll likely want to bring you more than that, trade them! You will always need egg cartons.
Good Luck!