$150- $300, depending on makers mark, color and size.
I have different sizes and colors some kk makers Mark which will cost more. Also the larger the ball the bigger price. Get a great vintage authentic highly collectible item in the states back to the states. Awesome Japanese souvenir to look back upon your time here. Do not fall for the new Chinese tourist rip off balls sold at tourist sites and Pier One, these old vintage ones have imperfections, bubbles, scratches etc.
At Camp Courtney often, near Kadena and Foster twice a week. I can accept paypal payments in person.