Toothbrush?

The neatly dressed salesman stopped a man in the street and asked,  Sir,would you like to buy a toothbrush for ten dollars?" Aghast, the man said, "I should say not, That's robbery!" The salesman seemed hurt.

"Well, then, how about a homemade brownie for five cents?" This seemed fair, and the man handed a nickel to the salesman. Unwrapping the brownie, he took a bite; suddenly the man spit out the mouthful "Say," he snarled, "this
brownie tastes like dirt!" "It is," replied the salesman. "Wanna buy a toothbrush?"