Babbitt is one of those dudes who spends most of his time doing math in his head about how much money he's making. And as we find out from the narrator,
The effect of his scientific budget-planning was that he felt at once triumphantly wealthy and perilously poor, and in the midst of these dissertations he stopped his car, rushed into a small news-and-miscellany shop, and bought the electric cigar-lighter which he had coveted for a week. (5.2.6)
Why does he buy the cigar-lighter, you ask? To make himself feel better.
To put it another way, the electric cigarette lighter represents Babbitt's dependence on retail therapy to make himself feel good about his life. Not having a good day? Just go out and buy something. After all, nothing feels better than spending money, right?
Especially when you're buying a thing, some object that can make you feel better about who you are as a person for just an instant. "Ooh, after I buy that grape-peeler I won't just be Joe Shmoe," you think, "I'll be the kind of awesomepants guy who owns a grape-peeler." Babbitt's line of thinking is pretty close to this one.
On top of all that, Babbitt also has a passion for anything and everything gadgety. In fact,
He had enormous and poetic admiration, though very little understanding, of all mechanical devices. They were his symbols of truth and beauty. (6.1.2)
We're going to stop short of saying that a cigarette lighter is a symbol of truth and beauty. But this description goes to show us how much Babbitt believes in business, technology, and progress. After all, mechanical devices have one set purpose: a grape-peeler is only supposed to peel grapes, and doesn't spend dark, lonely nights worrying about its cosmic purpose. That kind of mechanical thinking sounds super-appealing to troubled ol' Babbitt.