There are two variants of this coin with minor differences. One with 14 leaves in Victoria's laurel and a narrow date, the other with 15 leaves and a normal wider date.
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.
The die flaw on the British 1946 Penny is a small mark after the ONE on the reverse (ONE').
Their is no standard value for coins with gas bubbles, I have never seen or heard of proof coins with this defect but that don't mean it's not common. I do strongly suggest showing it to as many collectors and dealers as you can and do more research. It may take some time but I think it will be worth it.
Very little - unless it's in mint condition, or there is a flaw that makes it collectible. There were thousands of them produced in pre-decimal years !
It depends on the specific stamp and the type of flaw. A flaw caused by a cracked plate can be important, but may not create a large change in value.
Without knowing what sort of flaw the coin has, it is not possible to give a value. Please submit a new question and include a description of the flaw.
There are many different possible errors that can occur when bills are printed. Please post a new, separate question with more details about the flaw.
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.
You need to describe what the flaw is in order for us to get a better understanding of what exact error (or damage) you have. Chances are, if its a common silver certificate and it is an error it will raise its value. However, if it was done after the note left the press it is considered to be damage and will negatively impact its value.
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.
claw flaw
I can't won't ever do it.
A British 1917 Penny, uncirculated and in absolute mint condition could fetch up to £45 GBP. If it has been circulated but still in good condition, it might fetch anything from £3 to £15 GBP. If the extra metal is there because of defacing or mutilating of the coin, it will probably render the coin valueless. If the extra metal is there because of a genuine minting flaw, the coin may 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.