Driving a brand new car feels like riding around in an open billfold with the dollars flapping by your ears as they fly out the window.

The line is a comic, vividly physical metaphor for depreciation and conspicuous consumption. A “brand new car” is framed less as freedom or status than as a mechanism for rapid wealth loss: the open billfold suggests exposure, vulnerability, and lack of control, while the “dollars flapping” and “flying out the window” turns an abstract financial concept into an immediate sensory experience. The humor depends on exaggeration, but the underlying point is practical—newness carries a premium that evaporates quickly, so the pleasure of novelty is shadowed by the awareness of money being converted into diminishing value.