Pop! Goes the weasel.
A traditional English nursery rhyme, 'Pop! Goes the weasel', written back in the 18th century, was very popular once. One of its alternative interpretations involved references to pawning. 'Pop' was the slang used for 'pawn' and 'weasel' was the slang used for 'coat'. The line, therefore, meant "trading one's coat for daily bread."