If your Australian 50 cent coins have been circulated, probably not much more than face value, since coins from most years are still in circulation. Individual coins have a value determined by the past year or two of buying and selling coins between dealers and collectors. Not all years of Australian 50 cent coins had "Proof" coins minted. A "complete" set of mint "uncirculated" coins could be valuable, but don't make plans for retirement. I recommend that you take your collection along to a reputable coin dealer will be able to give you an accurate valuation.
There is no Australian "cent" from 1938. Decimal currency was introduced in Australia in 1966.
There is no Australian "cent" from 1939. Decimal currency was introduced in Australia in 1966.
Such a coin does not exist. The Australian "cent" coins were first introduced in 1966.
Decimal currency was not introduced into Australia until 1966. There is no such thing as an Australian pre 1966 cent.
There is no Australian 1954 20 cent coin. Decimal currency was introduced in 1966.
There is no Australian 1950 20 cent coin. Decimal currency was introduced in 1966.
Such a coin does not exist. The first Australian 20 cent coins were issued in 1966.
Such a coin does not exist. The first Australian 10 cent coin was issued in 1966.
Such a coin does not exist. There were no Australian 1967 50 cent coins minted.
Such a coin does not exist. The first Australian 20 cent coins were issued in 1966.
The Australian 2 cent coin was introduced at the changeover to decimal currency in 1966. There were no Australian "cent" coins minted prior to 1966.
Such a coin does not exist. The Australian 2 cent coin was first issued in February 1966.