Saw this at Coles Rochdale (QLD) - Cadbury Dairy Milk Creme Egg Chocolate Block 180g. That's $0.56 per 100g. Many blocks available. Might be available at other Coles perhaps?
Cadbury Freddo 180g Share Pack (15 pieces) is also $1 - but low stock
And Arnott's milk chocolate Iced Vivo 170g reduced to $1 - but also low stock