why are women's undergarments so expensive?

i spent eighty bucks today, and consider it a good deal. the price of an item should be directly proportional to the amount of fabric. a pair of plain cotton underwear at victoria's secret is priced at $8.50. of course, its also 5 for $19.50, so why not be truthful and just put $3.90 on the price tag? even that is way too much.... (and i know boxers are expensive too)

Z0nk5: bras don't come any cheaper?
Gidget1300: cheapest you see is like 20
Z0nk5: dang
Z0nk5: i should go into business
Gidget1300: victorias secret, they're like 25-40 bucks
Gidget1300: thats for normal bras. then they have the 'decorative' underwear, which is another story
Z0nk5: decorative hehe