While this is a modern item, I thought someone might be interested. It is an oversized postcard (size 10.5" x 4.5") on very rigid stock:


Unfortunately, a scan doesn't do it justice, since the photograph is 3-D and I had to reduce the image to fit it in this post. Nevertheless, the original looks as if the car is jumping out at you...very effective advetising.
It was probably an expensive way of advertising, too. Of course, if you can afford a Mercedes C-Class, you can afford paying for their elaborate advertising (which you usually do in the price of the car!)