What are at least three uses of symbolism in "A&P" by John Updike?

As the girls in bathing suits walk away from their interaction with McMahon, the clerk at the A&P's meat counter, Sammy, observes "old McMahon patting his mouth and looking after them sizing up their joints." The author may be suggesting, for argument's sake, that the girls have offered themselves up to the male gaze, choosing to appear in a grocery store in bathing suits. The fact that McMahon sees them as pieces of meat is symbolic, but in a sly sense. The scene may be intended to raise the question of the girls' complicity in their own objectification.
Sammy's description of Queenie purchasing herring snacks and the mental picture it suggests to him of stylishly dressed upper middle class adults drinking martinis contrasts with his description of his own family's "lemonade and if it's a real racy affair Schlitz in tall glasses with 'They'll Do It Every Time' cartoons stenciled on." The snack symbolically suggests another way Queenie might be out of Sammy's league, so to speak.
As Lengel tries to counsel Sammy into not quitting his job, Sammy punches "the No Sale tab" on his cash register. He is symbolically not buying Lengel's counsel. He has taken a stand on principle and must follow his own moral compass.