The most valuable Australian general circulation 50 cent coin would be the 1973 coin, which in absolute mint condition might fetch up to $60 AUD.
There were 4.009 million minted.
A reputable coin dealer will be able to give a more accurate valuation.
These coins are potentially still in circulation so, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they are worth 50 cents.
The most valuable American coin in current production is the half dollar. This half dollar is worth 50 cents when used.
The most valuable coin in the world is the Flowing Hair Dollar. This coin was minted in 1794. This coin last sold in 2013 for just over ten million dollars.
The Australian One Dollar coin was first issued in 1984 and has not been around long enough to be either rare or valuable. These coins are still potentially in circulation so, unless they are part of a Proof or uncirculated mint set or are individual Proof or uncirculated coins and in absolute mint condition, they are worth One Dollar. An Australian 2000 One Dollar coin, uncirculated and in absolute mint condition could fetch up to $50 AUD. There were 7.592 million minted.
The most valuable Australian Two Dollar note, in mint uncirculated condition, would be the 1968 (Coombs/Randall) note in the serial range FKD to FPS which might fetch up to $295 AUD.
The Australian coin that seems to consistently have the most minted for general circulation each year is the One Dollar coin, including commemoratives.
From least to greatest: Penny Nickel Dime Quarter Half Dollar Gold and Silver Dollar
The most valuable coin to sell at auction is the 1794 silver plugged dollar graded SP66 by PCGS. However,the most valuable coin is the 1849 $20 gold piece . It is unique and has an estimated value of $15,000,000.
After the abolition of the Guilder, the new most valuable coin would be the 2 Euro coin
SIMPLE ANSWER: The 1928 Philadelphia issue (no mintmark) coin. Average retail value is $275.00 for a coin graded G-4.
The fabled 1804 dollar is arguably the most valuable coin in this series. However, in reality none were struck in 1804! You can see pictures and read a bit at the following link.
Although the Australian 2 cent coin was withdrawn from circulation in 1994, they are still legal tender and are worth 2 cents. There are two Australian 2 cent coins that are considered to be valuable, the 1967 and 1968 coins, both minted at the Perth Mint. What makes them valuable is the missing designers initials (SD) below the lizard and to the left of the front right claw.
The Proof 1998s Silver Matte Finish $300.00 per Red Book.