Sonic drive-in's are extremely common in the Deep South. Nearly every single small town has at least one, some have several.
Food is meh-to-sometimes-passable depending on what you get where, not cheap though. Even some of the "value menu" items are around $2. Good ice cream. Vanilla cone for $1.00, not bad eating. They charge an extra 30 cents for a dish though!
I used to think it would be kind of cool if Sega had went into a co-branding agreement with them, but I can see I would've never worked. They more than likely would have wound up in a legal fight over it at some point. Nowadays both the games and the food are overpriced garbage anyway.