http://www.sonicdrivein.com/prmtns/2009/croissonic/index.jsp

Sonic Drive-in printable coupon: Free CroisSONIC sandwich w/ large drink purchase
Participating Sonic Drive-in restaurants are offering a CroisSONIC breakfast sandwich for free when you buy a large beverage via this printable coupon. (You will be emailed a link to print out your individual coupon.)