Sonic has released a new Buy One, Get One FREE Premium Chicken Sandwich  coupon.
You can get either a classic or asiago cheese chicken sandwich for free when you purchase another one.
Here is the fine print:
Choose between grilled or crispy whole chicken breast fillets served with fresh lettuce and hand-sliced tomatoes on a warm, whole grain ciabatta bun. For a limited time, try our Asiago Caesar Chicken Sandwich made with Asiago cheese and signature creamy Caesar dressing.
Be sure to catch their $.50 corn dogs as well on Halloween !