This varies widely on the type of coin, denomination, material, condition, mint, and many other factors. Be a bit more specific please :-)
The date and mint mark are on the the edge of the coin
The mint mark by itself isn't worth much. It has to be on a coin. If you do have a 2001 coin with a D mint mark, it's far too new to have any special value unless it's a high-quality uncirculated coin.
Nothing
$680 to $27,500 depending upon the mint mark and the condition of the coin.
A typical Mint State coin is about $50.00
It depends on the condition of the coin. A poorly conditioned coin is worth about $18. A perfectly conditioned coin is worth about $23,500.
19.95
A dollar.
About $40
it depends on how old it is.
That depends on the mint mark, purity, condition, rarity, age and size of the coin.
The current Coin Dealer Newsletter lists its value at about $1.75More: It depends on where it was minted and what mint state the coin is in. The 1946 Jefferson Nickel was minted in Philadelphia, Denver and San Francisco. According to USA Coin Book, these are the vales:Philadelphia (no mint mark): In MS60 mint condition, this coin is worth about $0.70, while a coin in MS65 Brilliant uncirculated mint condition is worth about $5.50.Denver (small "D" mint mark): In MS60 mint condition, this coin is worth about $0.95, while a coin in MS65 Brilliant uncirculated mint condition is worth about $5.50.San Francisco (small "S" mint mark): In MS60 mint condition, this coin is worth about $0.95, while a coin in MS65 Brilliant uncirculated mint condition is worth about $3.25.A Mint State 1946 Jefferson Nickel (note spelling) in MS-60 is 40 cents, in MS-63 it's $2.75. If you found it in change, it's likely not uncirculated.