Half price Sonic shakes December 21 Dec 192012 Participating Sonic drive-in restaurants are offering shakes for half price. Mention the discount when ordering a frosty treat December 21, which happens to be the Winter Solstice. Thanks to Wichita on the Cheap for the info. If you're new here, you may want to subscribe to our daily email updates. That way, you won't miss a deal. Thanks for visiting! Leave a Reply Cancel reply Name (required) E-mail (required) URI * Copy This Password * * Type Or Paste Password Here * Your Comment You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong> Notify me of follow-up comments by email. Notify me of new posts by email.