In a junk store that she often frequents, Esperanza and Nelly encounter a music box that is so beautiful it can only be described through simile, although the store owner ironically refuses to sell it:
Then he starts it up and all sorts of things start happening. It’s like all of a sudden he let go a million moths all over the dusty furniture and swan-neck shadows and in our bones. It’s like drops of water. Or like marimbas only with a funny little plucked sound to it like if you were running your fingers across the teeth of a metal comb.... This, the old man says shutting the lid, this ain’t for sale.
Esperanza's transcendent musical experience requires consecutive similes to explain. The use of similes conveys Esperanza's childlike perspective on the world: when she has these amazing and new experiences, she struggles to explain them without gesturing towards other, more familiar experiences.
The moment is also one of situational irony, as the man who owns the junk store doesn't want to sell the music box to two children who frequently browse the store. Considering that the man owns a store, where he attempts to sell antique and thrifted items for profit, the fact that he won't sell a music box is ironic and counterintuitive. By refraining from selling the music box, the man suggests that some things are more important than money: namely, experiences and memories. For the owner of the store, this unassuming box is more important than the money he could sell it for, almost certainly because its music evokes positive memories for him (similar to the Spanish music Esperanza's dad listens to as he shaves). The House on Mango Street urges readers to privilege experiences above all else, and this instance of figurative language is one example of what doing so might look like.