What is the value of an Australian 50 cent piece made in 1966, 1977, 1988?
The 1966 50 Cent piece is made of silver, and has about .36 Troy ounces of that precious metal, worth perhaps US $4.50 today. The other coins, if in average circulated condition, are essentially just worth their face value, if used in Australia. The 1977 and 1988 coins are both commemorative coins, minted in copper-nickel, but are fairly common. The 1988 had a modestly low mintage of 2-3 million, and might have some modest value – it has a retail catalog value of about US $2 – if in unused, as minted condition. You can find values for coins of the world, including Australia, by using online or paper guides.
