Posters are usually used to define or market a product or a service. The cooler it looks, the better. In my opinion, the vintage ones are the most attractive, appealing of them all.
After all, the identity of a product or service is found in the poster, that will generate that “wow” effect in the eyes of the viewer and turn him into a customer.
http://elcheapoposters.com/ is all about vintage posters that can be used for event planners, dealers, framers or by anyone looking for a cool vintage poster.
The above website offers vintage posters of all categories: circus, movies, travel, Sci Fi, etc.