Estela's Swap by Alexis O'Neill (2007)
Estela is attending her first swap meet, where she plans to sell a music box to make money for lessons with the Ballet Folklorico. When a strong wind ruins the flowers the woman across from her is selling, Estela decides to give her the music box so she can listen to cheerful music while she makes new flowers. Although Estela may not have enough money for the lessons, her heart is full. And in this charmingly illustrated story, the flower seller has a wonderful surprise for Estela.