Such a coin does not exist, the Royal Australian Mint did not produce any commemorative coins in 1973. You may have a souvenir token or medallion which would have been sold at the opening in 1973. In mint condition, it might get a dollar or two.
Alternatively, you may have a 1997 pure silver "Landmark series" Ten Dollar coin which, in mint condition and the original packaging, could fetch up to $99.00 AUD.
A reputable coin dealer will be able to give a more accurate valuation.
What is World War 1 Commemorative worth
Which commemorative? Wyoming Diamond Jubilee? What condition? sales@countrygunsmith.net
There was no Postal Commemorative Society in 1786
to get a value, you must have it professionally appraised.
100-2000 USD
Current value is about $7
Of the countries issuing a Florin (Two Shilling) coin, only Australia ever issued a commemorative Florin, but there were no commemorative Florins issued in 1936.
Face Value
$125
August 18, 2009 The Jamestown 400th Anniversary Commemorative Coin was issued in silve and in gold. In silver the uncirculated value is about $35. In gold the uncirculated value is about $230.
The only commemorative dollar struck that year honored the Marquis de Lafayette. Its retail value could range from $200 to $400 depending on condition.
The value of Los Angeles Olympics commemorative silver dollar varies and depends on the one you have. An estimate for most are 38 to 40 dollars.