Is art really worth the value it reaches at auction? Take Leonardo Da Vinci's Salvator Mundi - that fetched $US450m at a Christie's auction recently. Or in NZ, a Colin McCahon work recently broke the $1 million barrier ... the same work sold for $500 in 1969. Bronwyn Coate recently wrote about what she calls "the economics of ridiculously expensive art". She's a researcher in cultural economics at RMIT university in Melbourne - her research explores different aspects of art and culture with a focus on the economics implications of art.