Both of these coins are still potentially in circulation.
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 and One Dollar respectively.
There were no Australian Fifty Dollar notes printed in 1984.
The first Australian Dollar coin was issued in 1984.
Australian one-dollar coin was created in 1984.
The last Australian One Dollar notes were printed in 1982. The Australian One Dollar coin was first issued in 1984. The One Dollar notes were progressively withdrawn from circulation from 1984.
The Australian One Dollar coin was first issued in 1984. The Australian Two Dollar coin was first issued in 1988.
The Australian One Dollar coin was first issued in 1984 replacing the Australian One Dollar note which was last issued in 1982. The Australian One Dollar note was progressively removed from circulation in 1984. The Australian Two Dollar coin was first issued in 1988 replacing the Australian Two Dollar note which was last issued in 1985. The Australian Two Dollar note was progressively removed from circulation in 1988.
The only significant change to the Australian currency in 1984 was the replacement of the One Dollar note with a One Dollar coin.
Such a coin does not exist. The Australian One Dollar coin was first issued in 1984.
The last Australian One Dollar notes were printed in 1982. The Australian One Dollar coin was first issued in 1984. The One Dollar notes were progressively withdrawn from circulation from 1984. They are still considered to be legal tender and will be accepted by banks.
Presumably, you refer to the 1 Dollar coin(?). An Australian 1984 1 Dollar coin, uncirculated and in absolute mint condition could fetch up to $15 AUD. They are still in circulation, so unless they are part of a proof set or as previously described, they are worth 1 Dollar. There were over 186 million minted. A reputable coin dealer will be able to advise a more accurate quotation.
The last Australian One Dollar note was issued in 1982 and they were progressively withdrawn from circulation after the introduction of the One Dollar coin in 1984.
Such a banknote does not exist. The Australian One Hundred Dollar note was first issued in 1984.