The difference between the narrator’s idea of what the Araby market will be like (exotic and enchanted) and how it really is (expensive and mundane) is an example of situational irony. After the narrator’s crush (Mangan's sister) first tells him about the market, he reflects on the word “Araby,” clearly believing that the market is an exciting and alluring place:
The syllables of the word Araby were called to me through the silence in which my soul luxuriated and cast an Eastern enchantment over me.
The narrator has spent his whole life in a poor neighborhood in Dublin, and his explicit desire for the “enchantment” of the market sets up the possibility that he will be able to escape the harsh circumstances of his life. Unfortunately for the narrator, what he finds at the market is not an “Eastern” escape but a market full of everyday items like “porcelain vases and flowered tea-sets” sold by British people who treat him like he is an inconvenience. Instead of being the catalyst for liberation from the constraints of the narrator’s dull daily life, Araby merely reinforces his position as a poor kid from Dublin easily ignored by British people, mirroring how the people of Ireland are (at this time in history) ignored by the British government that rules them.
In addition to the political implications, Joyce’s use of situational irony here also suggests that while coming of age can be empowering for some, for others—especially those without financial resources—it can be experienced as a loss of innocence. The narrator leaves Araby disillusioned and (readers can imagine) unlikely to seek escape in romantic love or enchanted markets again.