There can be several reasons for this phenomenon:
A proof coin is worth more because it was struck by a custom stamping process. These coins were not minted for circulation, but minted for collectors. The quality of minting is far beyond that of coins minted for circulation.
There is also another reason this happens,, example>>
a 1970-S(san francisco) small date:proof set retails for about $90 dollars..
they take the coins out of the holder and send them to be graded,the coins will most always get the highest grades depending on the grading service used...usually a MS/PR-70 or MS/PR-69 is common.....they then resell each coin the 1970-S small date penny with a red color certified MS69 or MS70 sells for $950.00 for one penny!!!!!
They have paid for the proof set and grading fees for all 6 coins with the sale of the single penny they had graded..................lots and lots of money......you see many single coins on eBay for hundreds even thousands and they have came from a proof set,and are worth 10 times more because they carry the high MS/PR grades................
If the coin is a Proof coin it is worth about $20 USD. If it is not a proof coin and is uncirculated it is worth about $12 USD. (2/28/2010)
The Mint issued clad and silver State Quarters (5-coin) proof sets. Post new question as to what type of sets.
the 3 coin proof set with 2 silver proof one dollar coins and one 10 dollar proof gold coin is worth about $550.00 retail the 3 coin proof set with 2 silver proof one dollar coins and one 10 dollar proof gold coin is worth about $550.00 retail
Face value only, unless it's a proof or Silver proof coin in its original packaging. Then it's worth about £8 for a proof or around £20 if it's a silver proof.
The 1993 5 coin proof set sells for about $7.
An American Silver Eagle coin's worth depends on the coin. Most proof versions are worth around $85 whereas and uncirculated versions are worth around $55-$100. Some issues are worth a large sum, such as the 1995-W proof, which is worth $3,500.
The "S" mintmark denotes this coin as a Proof coin. Unless it has been handled correctly it's only one cent. The Mint does not sell single one cent proof coins. If the coin is still in collectible condition, the value is about $2.00.
This depends on whether the coin is a 1990 or 1990 Proof coin. A 1990 gold coin with a face value of $10.00 that weighs 0.25 ounces is worth approximately $390. A 0.25-ounce 1990 Proof coin is worth approximately $420.
Current retail is $18.00 for this coin
The S mint mark on the coin identifies it as a proof coin that is only sold in proof sets from the mint. The retail value of a proof 1997s is $16.10 but if the coin was found in a bank roll or in change, it's now only worth face value.