Half-Price Drinks and Slushies Today at Sonic! 5 years agoAdd Comment This post may contain affiliate links. For more information please see our Disclosure Policy. Hopefully your taxes are all done! Today is tax day so to celebrate Sonic is offering ‘happy hour’ all day! Which means you will be able to score half-price drinks and slushies all day long today (Tuesday)! See you at Sonic! Share this with your friends!