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
Face Value
$125
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.
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.