Dresses sure are cheaper now than they were in the late 80's/early 90's, though!
I went to one prom my sophomore year, two in my junior year, and two in my senior year. That's three dresses that cost between $400 - $600 apiece!! That was when the handbeaded silk dresses were in style.
Of course, each year I had to wear the same dress to both proms, and in the beauty pageant that year, and anything else that required a formal dress. They weighed more than I did!! (I'm in the blue...BTW..don't laugh, it was 1994!)
I was relieved when I got to college and the simpler, cheaper dresses came in style. I had to have at least two per year for sorority functions, and it was a lot cheaper to go to Macy's or Dillards and pluck one off the rack for around $100 apiece!