From (season 3 Episode 8) “Lisa’s Pony”
When Lisa requires a new saxophone reed for her talent recital, she asks Homer, who immediately promises to buy her one. Though when Homer breaks his promise, he makes up for it by giving Lisa the one thing she had always wanted, a pony named Princess. With a new pony in the house, Homer struggles with two jobs to cover the cost. Lisa, upon seeing what Homer must go through to pay for the pony, decides to sell it.