Irony in the Ransom of Red Chief

In the story the Ransom of Red Chief, I think the mist important quote in the book is when the father of boy asks for 250 dollars to take the boy back because it introduces the main feeling of irony in the story. This is also enhanced by the fact that the two main characters end up paying the father the money to take the boy back because they think they'll go mad if he stays around them any longer.