Please look at the coin again, the only series of Standing Liberty coins are quarters and none are dated 1906.
A very common coin average value is $2.00-$5.00 for most coins
Because this date is so common most are only valued for the silver, about $3.00
There were no British Crowns minted from 1903 to 1926 inclusive.
With the possible exception of traders tokens (with the traders business name on them), there were no "Australian" Halfpennies minted prior to 1911. The only Halfpennies circulating in Australia...