What the? ... Shoppers spotted this hilarious sale item is a Woolworths store in Sydney. Picture: Heidi Tiltins

The sale item, a ‘Little Live Pets Butterfly House’, was photographed and posted to social media, after being spotted by a number of shoppers at a Woolworths store in Dural in Sydney’s north west.

The deal was also posted on the Woolworths website online.

1 cent saving ... the product was also online today on the Woolworths website.Source:Supplied

The ‘Cheap Cheap’ special offered customers a 1 cent discount, reducing the cost from $20 to $19.99.

If our calculations are right, given the 1 cent coin’s withdrawn from circulation in 1992, the cost of the product would be rounded back up to $20 on purchase.

News Corp Australia has contacted Woolworths for comment.