The coins are valued between $50 and $100. They coins are not common and the price can vary depending upon its condition.
There was no New Zealand 1949 Threepence minted.
rhodesia and nyasaland 1958
Such a coin does not exist. The Threepence was not introduced into the British currency until about 1550.
Rhodesia Elizabeth the second 25c 1964
The British Threepence is part of a redundant currency that was withdrawn and demonetised in 1971. It no longer has an exchange rate with other currencies.
There were no Australian Threepences minted prior to 1910.
Modified coins have no collector value. The ring may have some value.
Any collector value would depend on the country of origin and the condition of the coin.
The Australian 1955 Threepence looks the same as all Australian Threepences minted from 1953 to 1964 inclusive. From 1947 to 1964, their composition was 50% silver, 40% copper, 5% zinc and 5% nickel. They had a plain edge, weighed 1.41 grams and were 16 mm in diameter. The Australian 1955 Threepence has Queen Elizabeth II on the obverse, and the reverse design shows three stalks of wheat with the year split either side of the stalks, AUSTRALIA across the top and THREEPENCE across the bottom. Pictures of a specific coin are difficult to come by. Frequently you should be able to find one on eBay, but the picture is withdrawn after the coin is sold.
Three old pence = 1/80 pounds = 1.25 pence.
Modified coins have no collector value. The ring may have some value as a piece of jewellery.
The only British 1831 Threepence issued was the Maundy Threepence. A British 1831 Maundy Threepence (FDC), uncirculated and in absolute mint condition could fetch up to £40 GBP. If it has been circulated but still in good condition, it might fetch up to £20 GBP. A reputable coin dealer will be able to give a more accurate valuation.