Market Play

http://commons.wikimedia.org/wiki/File:Phineas_Taylor_Barnum_portrait.jpg

Barnum used to bring consternation into the hearts of his grocers by complaining that their pepper was half peas. When they protested, he would quietly ask, ‘How do you spell pepper?’ and the catch stood revealed.

— William Shepard Walsh, Handy-Book of Literary Curiosities, 1892