Five bucks (U.S.) will get you 25 of these “You are a Douche” cards from Orange32. Here’s their description of these cards:
Tired of arguing with complete morons? Tired of getting into bar room brawls? Well now avoid the confrontation with our glorious Douche Card. Simply hand it to the asshole in question and walk away. Problem solved.
Whether a single order will suffice will depend on your line of work and the company you keep.