It is extremely unlikely that a 2000 general circulation coin would be minted in 2001.
It is not so unlikely that some bullion Proof coins might be minted in the year after the date indicated on the coin.
Such a coin does not exist. There were no Australian 1967 50 cent coins minted.
Such a coin does not exist. The first Australian Penny was minted in 1911.
The Australian 1985 One Dollar coin does not have a mintmark. They were all minted at the Royal Australian Mint Canberra.
All 1988 Australian coins were minted at the Royal Australian Mint Canberra. Since they were all minted at the same place, there is no mintmark.
An Australian 2000 1 ounce gold nugget coin ($100 Year of the Dragon), in absolute mint condition could fetch up to $1,250 AUD. There were 30,000 minted. A reputable coin dealer will be able to give a more accurate valuation.
An Australian 2000 Olympic Five Dollar coin (A Sea Change 1 - Proof - 99.9% silver), in absolute mint condition could fetch up to $75 AUD. There were 0.1 million minted. An Australian 2000 Olympic Five Dollar coin (A Sea Change 2 - Proof - 99.9% silver), in absolute mint condition could fetch up to $55 AUD. There were 0.1 million minted. A reputable coin dealer will be able to give a more accurate valuation.
The Australian Penny was issued in most years from 1911 to 1964 inclusive. Depending on their condition, the year they were minted, where they were minted, and any peculiarities of the coin, they could be worth anything from 50 cents to thousands of Dollars.
Sacagawea
An Australian 2000 gold Proof Sydney 2000 Olympics coin 4 set, in absolute mint condition and the original packaging, could fetch up to $1,760 AUD. There were 3,000 sets issued. An Australian 2000 gold Proof Sydney 2000 Olympics coin 8 set, in absolute mint condition and the original packaging, could fetch up to $3,595 AUD. A reputable coin dealer will be able to give a more accurate valuation.
The only Australian coins minted for general circulation in 2007 were the 5, 10 and 20 cent coins and the 2 Dollar coin. The 50 cent coin was only minted as a Non-Circulating Commemorative and, the 1 Dollar coin was only minted for Uncirculated or Mint year sets and Proof sets.
The first Eire Punt (One Pound) coin was minted in 1990, the last was minted in 2000.
The last Australian Penny was minted in 1964. Their place in the Australian currency was replaced by the 1 cent coin in 1966.