something out of Arthurian legends in the market:

These noises converged in a single sensation of life for me: I imagined that I bore my chalice safely through a throng of foes. Her name sprang to my lips at moments in strange prayers and praises which I myself did not understand. My eyes were often full of tears (I could not tell why) and at times a flood from my heart seemed to pour itself out into my bosom.

Clearly, we are seeing a boy in his first flush of love. He treats the request to buy something from the bazaar as a noble quest and sees himself as some kind of knight errant. It is only when he reaches the bazaar that he sees it, and his supposed love, for the drab, insubstantial thing that it actually is and reality comes crashing down around him. Reality and fantasy are completely opposed in this novel, and for a time, the forces of imagination seem enough to keep dull reality at bay. 

A classic example of this occurs when the narrator goes to the market and is surrounded by the everyday jostle and bustle of an Irish meeting place. What is key to focus on is the way that the narrator is so consumed with his romantic notions and illusions about his love for Mangan's sister that even such signs of reality are transformed in his mind as further evidence of his romance:

We walked through the flaring streets, jostled by drunken men and bargaining women, amid the curses of labourers, the shrill litanies of shopboys who stood on guard by the barrels of pigs' cheeks, the nasal chanting of street-singers, who sang a come-all-you about O'Donovan Rossa, or a ballad about the troubles in our native land.  These noises converged in a single sensation of life for me: I imagined that I bore my chalice safely through a throng of foes.

The poverty and reality of Irish urban squalour, indicated by the references to pigs' cheeks, that were a common kind of food, is converted in the boy's imagination into a "throng of foes" that he must bear his "chalice" safely through. He makes of such an everyday drab and common scene a kind of Arthurian legend, showing how he deals with reality until the epiphany he experiences at the end of the tale.