As you could probably guess, styrofoam egg cartons bug the crap out of me. I usually buy the organic eggs from Safeway and they come in cardboard cartons. But when we got out to the Hutterite colony I can buy local eggs for less then half the price of the organic. Problem is, they come in styrofoam cartons.
So the last time we went out, I took the old, heirloom egg basket that I acquired from one of my grandmothers, and got the nice Hutterite lady (Sarah) to get me eggs without a carton. Straight from the cardboard flat, the eggs went into my basket and came home that way.
Now, the Hutterites will take the cartons back for re-use, but they can only be re-used so many times before they are worn out. This just takes me out of the loop and removes my responsibility for that carton.
Remember ... there are always options.
P.S. - if you have an option of buying eggs directly from the layers (or their owners) I don't think you need a special basket to do it - any basket should work. You're not tossing large crates around, so the egg carton really isn't necessary. I've been doing this now for more than 6 months - averaging about a dozen a week - and I haven't broken one yet! Even soft-shelled eggs. Just put them on the floor in the car and they arrive safe and sound at home.