The cans are labelled in several languages, with the primary text “Merda d’artista -- contenuto netto gr 30 conservata al naturale prodotta ed inscatolata nel maggio 1961”. This means something like "Artist's shit -- contains precisely 30 grams, naturally produced and conserved in May 1961."
At the time I write this, gold is trading for $11.11/gram. The Tate Modern paid 22,300 pounds for their can, which converts to $35,880 by today's exchange rates. This means that, as of today, Manzoni's shit is worth $1196/gram, or more than 100 times as much as gold.
Manzoni died in 1963 due to alcohol abuse. His intended satire has become example #1 in any argument over whether or not modern art is essentially nonsense.