the horse-jawed housewife returned to the tv screen , winding up the commercial ; her voice softer now , she trilled , `` if the home-art store that you patronize does n't yet carry ubik , return to your conapt , mr. chip , and you 'll find a free sample has arrived by mail , a free introductory sample , mr. chip , that will keep you going until you can buy a regular-size can . ''