It would vary on the breed of geese really. Also if the breeding stock is shown and won, and quality of the birds who's eggs you are offering for sale.
Eating eggs are different, I would say sell each egg for 1/4 the price that you'd sell a dozen chicken eggs for, since a goose egg is about equivalent to 4 chicken eggs. Here, that would mean $.25 an egg, but people are real cheapo's here!
1/4 the price of a dozen free range chicken eggs would price them at .60 cents to $1 an egg around here. Since that is less than the going price for a blown-out goose egg shell, I wouldn't sell one that cheap.
My opinion: goose eggs are the very best tasting eggs of all. If you have a customer that appreciates the fine quality, they should be willing to pay for the eggs.