Are you talking about California Mountain Kings, Lampropeltis zonata or when you say banded are you talking banded cal kings? (Lampropeltis getulus californiae)
Either way they both cost between 40-200 bucks depending on your location, and quality. I would assume up here zonata would cost quite a bit more than a cal king because they are not as common. In the states though I would assume their prices are somewhat reasonable like cal kings.