Sammy wears the store uniform of a white shirt his mother irons, a bow-tie that belongs to the A&P, and an apron with his name embroidered in red on the pocket. Everything he wears signifies that he is an employee of the store, there to serve customers and earn a living. The uniform sets him apart, so that people who need help can find him. It also signals that the store is an orderly place with rules and regulations.
The girls, on the other hand, come in very self-confidently in nothing but their bathing suits. Unlike Sammy, they are outsiders who have come to the beach on vacation. They wear leisure clothes because they don't have to work. The girl who Sammy calls Queenie walks with a regal self confidence:
She didn't look around, not this queen, she just walked straight on slowly, on these long white prima donna legs. She came down a little hard on her heels, as if she didn't walk in her bare feet that much . . .
The different clothes Sammy and the girls wear accentuate their class differences. Sammy's manager, Lengel, tells Sammy as he quits that he doesn't want to do this to his parents, suggesting the family needs the money his job brings in. Sammy's uniform shows him conforming to a code that the privileged girls can ignore.