I had a great burger here - The "Slaty Beef Burger" - with sour cream caramelised onions, it was probably the best burger I've ever had!
This was while the Tour Down Under was in Willunga, and it was teeming with tourists - they could've taken advantage and pushed their prices way up, but they didn't. Lovely outdoor dining area, with plenty of shade-giving umbrellas in very hot weather, service was really friendly and fast. Would highly recommend!
Approximate cost: $11.90