Eric Berne
Author: Eric Berne
Publisher: Grove Press (1972)

A woman came home from a group meeting one day where she had heard [the concept of psychological trading stamps] for the first time, and explained it to her twelve-year-old son.  He said, 'Okay, mom, I'll be back soon.'  When he returned, he had made a small roll of perforated paper stamps and a little dispenser to hold them, together with a paper book with the pages ruled off into squares.  On the first page he had written: 'This page, when full of stamps, entitles you to one free suffer.'  He understood perfectly.