For you that are selling at a market, do you pay a vendor fee to be there? When you say you sell out, approximately how many dozen are you selling?
I did a booth once, paid $20 for the stand, sold 10 dozen eggs for $2.00 a dozen (albeit it was a VERY SMALL market). I have better things to do with my day, since I can sell them out of my house for $1.50. If I take them to the local auction, they'll sell for $1-$2 a dozen and I get 75% of that. I did have a market vendor interested in taking my eggs this spring in much better farm market, but 2 others vendors showed up selling eggs this year.
A lot has to do with LOCATION.