as Jan says, Ive seen certain sellers, who are 'in' at the time, get ridiculous prices for their nappies.
Goodmamas are a recent example - regularly selling for over $200 a go, some over $300. I believe Fuzbaby had the same when they sold originally on ebay, Crankypants generally hit the $200 mark.
Its all about whats in fashion and hard to get.
Goodmamas seem to have shot themselves in the foot though by overstocking, their resale price has plummeted recently, though at least the designer cottoned onto the hype and sold on HC at auction herself, rather than middlemen buying up and passing on at overinflated prices.