Sonic | 1/2 Price Cheeseburgers TODAY! August 13, 2015 by Jamie 1 Comment Tweet Need a little treat towards the end of the week? Treat the family to Sonic tonight with 1/2 Price Cheeseburgers! *1/2 price SONIC® single-patty Cheeseburgers only. Limit 5. 8/13 only. Mention when ordering. See other Restaurant Coupons & deals.