The piece was created as part of Rural Women's Get Plastered for Breast Cancer initiative, an exhibition of plaster casts of women's busts.
Brown donated the glass piece to be auctioned, with funds donated to the New Zealand Breast Cancer Foundation.
Whanganui's most asked about auction was a "soul for sale", listed in July 2008.
Mr Hunkin said it attracted 162 questions but the listing was eventually withdrawn.
Trade Me expects to celebrate its billionth sales listing this week, almost 17 years after the business was created.
Whanganui's listings have made up 0.6 per cent of all New Zealand listings in recent years, according to Trade Me.
Trade Me chief executive Jon Macdonald said the company had seen its fair share of quirky, crazy and wonderful listings, and marvelled every day at the eclectic range of items put up for sale.
The most viewed listing of all time was the handbag and cellphone former All Black captain Tana Umaga is said to have used to whack Hurricanes teammate Chris Masoe in the Jolly Poacher bar in Christchurch in 2006. It received more than a million views.
Next was a "possessed" HP Printer, listed in 2013, which received 800,000 views.
Users asked 2224 questions when a seller offered a 20-acre farm free with the purchase of a tractor - making it the most asked-about auction of all time.
The next most asked-about auction was a "scary" washing machine.
