Caps for Sale: A Tale of a Peddler, Some Monkeys, and Their Monkey Business By Esphyr Slobodkina

"Caps, caps for sale," is the cry of the peddler walking through the town with a huge pile of caps on his head.  On this particular very slow day the peddler decides to take a nap under a tree.  When he wakes up he discovers his caps are missing and after a moment he realizes that they've been stolen by the monkeys in the tree.  The monkeys mimic his moves as stomps in anger and shakes his fists at them.  Kids are very amused by this simple tale.  It's a fun one to let them "read" back to you after you've read it to them once or twice.