Let's do some math (and err on the expensive side): Prom ticket: $100 Tux Rental: $250 Dress Purchase: $500 Limo rental: $750 Corsage: $50 Hair: $200
That's nearly $2k, but includes BOTH a dress and a tux, and assumes each kid gets a limo (rather than one limo transporting 4, 6, 8, or 10 kids. I'm not buying (literally and figuratively).
Poor people are more likely to employ outward “wealth signals” to others, because of their self conscious awareness of lack of relative success.
Conspicuous consumption among “the poor”:
http://www.slate.com/articles/business/the_dismal_science/2008/01/cos_and_effect.html