One of the most clever and deceptive marketing schemes ever was pricing gasoline with nine tenths of a cent added on to the end. I'm not sure why, but most people choose not to acknowledge the fact that this hidden cost is there, even though it says it on the sign. The sign clearly says $1.69 9/10, our minds seem to push out this fact. We think of the price as $1.69, when in actuality it is more like $1.70. I imagine that in the course of our lifetime, we spend hundreds of dollars on that little nine tenths of a cent they tack on.