Trader Joe's recently started carrying "Cultured Butter" made in Brittany, France. It has very subtle tang to the flavor, only $2.99 for 8oz, 30 cents less than KerryGold. Wrapper doesn't state grass-fed, but as assumed with European cheeses, most likely it is.
http://www.traderjoes.com/digin/pos...d-salted-butter

As an aside to this Butter thread, but if you are at TJs, also new is Cream on Top, Organic, whole -milk, grass-fed yogurt.