£1.50 at my Sainsbury's, but prices aren't the same across the country. But there's no whole leaf kale at the moment (out of season until June IIRC) so we're on the expensive stuff. Still better value than the chopped kale
We eat it, but we take the stalks out (Matt doesn't like them) and we have some conveniently cute waste disposers who're happy to finish off our leftovers. Cavolo nero is also really easy to strip off the stalks