There are about 7 varieties of "Iredale & Co, Sydney - Established 1820" token all with the denomination of 1 Penny. At least one of them is inscribed "BRITANNIA" and features the seated figure of Britannia.
The rest seem to have "Australia" over a standing figure holding scales.
The tokens do not seem to be all that rare and depending on the variant, a token in mint uncirculated condition could get anything from $250 to $300 AUD. If it has been circulated but still in good condition, it might fetch anything from $10 to $600 AUD.
A reputable coin dealer will be able to assist with identification and give a more accurate valuation.
Assuming average circulated condition, about $5.00
The Australian-born sons of convicts
James Martin - Australian politician - was born on 1820-04-14.
There were no British Farthings minted from 1808 to 1820 inclusive.
The value was 400. The value of numbers is not dependent on time!
There were no British "v" pence coins minted in 1820, or ever.
Sorry no US Lady Liberty dollars dated 1820
350$ dollars.
A 1820 penny - aka - Coronet Large Cent - was minted in 4 different varieties: 1820, 1820 (large date with a curl top 2), 1820 (large date with plain top 2), and a 1820 (small date with a curl top 2). All these coins in good condition (G4) are worth from $30 to $50.00.
The only US gold coin dated 1820 is a Capped Head Quarter Eagle ($5.00) gold piece. Three different varieties exist, the most common type has a minimum value of $3,500.00
Please check your coin, George III died in 1820.
Congratulations if you have one, but George III died in 1820.