In the US, it seems the average spend to go to 'prom' is US$807.
I nearly laughed out loud.
http://money.cnn.com/2011/06/16/pf/cost_of_prom/index.htm?iid=HP_River
I nearly laughed out loud.
http://money.cnn.com/2011/06/16/pf/cost_of_prom/index.htm?iid=HP_River