A British 1994 2 Pence coin may have had the copper plating removed. Any coin with a "genuine" minting flaw would have some value, above the usual, as a collectible coin. Genuinely flawed coins are not necessarily known about or documented until somebody turns up with one, since they are an "accident" of the minting process, and have escaped detection during quality control at the mint therefore, a valuation cannot be anticipated. A reputable coin dealer should be able to identify and confirm the coin as genuine and make a valuation. Flaws and errors on coins should not be confused with mutilation or mangling of the coin. It should be noted that many people have the interest, skill and enthusiasm to fraudulently alter otherwise normal coins for the purpose of personal gain or notoriety. Also, many coins are commercially produced for magic or trick purposes and these include "double headers/tails" and "impossible" coins like a US silver Dollar on one side and a British copper Penny on the other.
Error coins need to be seen for an accurate assessment, take to a coin dealer.Also please note that coins are said to be struck rather than "stamped".
Error coins need to be seen, take it to a coin dealer. Most errors are very common and add no value.
A standard 1965 quarter isn't a rare date. If it is overstruck with a nickel die, though, the value could be greater if it's a verifiable error. If the nickel image is reversed, it may or may not be an actual Mint error; if it isn't, it could've been done by anyone with a hammer after the fact, which would decrease the numismatic value (not to mention its ability to be used in a vending machine).
It may be a Mint error only in that the coin is an uneven thickness, in which case it would be a planchet error. If the coin is not damaged otherwise (excluding the bubble), though, then it's probably not a provable Mint error. The bubble is probably a lamination problem, which can also be a planchet error. This occurs when the cupro-nickel layer (the "silver" colored layer) separates from the copper middle.
This sounds like an approx. 90% off-center strike error. These regularly sell for about $10 to $15
It's difficult to provide an exact value without examining the coin, but a mis-stamped 1982 US nickel could potentially be worth more to a collector due to its rarity. Such coins are often evaluated by their degree of error, condition, and demand among collectors. I recommend consulting a professional coin appraiser or numismatist for an accurate valuation.
You could possibly have an error coin that was struck twice, or simply something that was altered by someone with a few tools and too much time on their hands. Items like these are best evaluated in person by a dealer or appraiser who works with error coins.
Please post a new question with the coin's date and a description of the error.
It's very difficult to evaluate a suspected error coin based solely on a description. These coins should be examined in person by a dealer who's familiar with minting mistakes.
This is a rare misstruck error and is worth up to $90.00 according to condition.
If the nickel is new but missing its date it could be a minting error or an altered coin. As with most suspected error coins it would have to be inspected in person to be sure.
I've seen nickels struck on cent blanks, but not cents struck on nickel blanks -- the blanks are too large for the feeder tubes. I suggest you contact Mike Byers -- an error expert. His website is here : http://mikebyers.com