My midget of data is that the local cage-free eggs have remained the same price for 3+ years now, but the "regular supermarket eggs" are now more expensive than the local ones.
I just bought groceries yesterday, and checking the Walmart I went to, this site was accurate at least for that location.
Of course free range eggs aren't totally safe either, there's been a few scandals where a company has just lied about the conditions of the chickens entirely and gotten away with it for a worrying amount of time.
I don't know of any large producers of pasture raised eggs. They all seem to be small, regional outfits, but then again, I haven't really looked hard.