I'm not sure of value yet but I found one of these in a box going through my fathers coin collection. It came with a certificate stating it's a 24k penny bearing the added date of 12-31-74 as the first day US citizen could legally own gold in over 40 yrs. It was made by American Consumer I believe.
Take it to a collector
No US quarters are dated 1975 they are all dual dated 1776-1976 and were struck in 1975 and 1976
The last Australian Penny was minted in 1964. There was never a 1975 Australian Penny.
No they did not strike any quarters, half dollars or dollars dated 1975
Laura Penny was born in 1975.
In For a Penny was created on 1975-11-14.
Unsere Penny - 1975 is rated/received certificates of: West Germany:o.Al.
The coin is still in circulation today and is only face value
Penny Phang was born in 1975, in Kuala Lumpur, Malaysia.
There are no U.S. half dollars dated 1975.
Please take another look at your coin. There were no 1975-dated half dollars; all dual-dated coins from the Bicentennial celebrations carried the dates 1776-1976 even if they were struck in 1975. There's more information at the Related Question.
1¢ It's a novelty item made by a private company by altering a genuine cent and selling it at an inflated price as a "collectible".