What you are describing is called an error coin and the value of such a coin depends upon the nature of the error. Please submit a new question giving more detail about the coin.
10 cents. They are in common circulation and the lack of a mintmark simply means the coin was minted in Philadelphia. Dimes did not have the "P" mintmark until 1980.
10 cents.
About a dime.
1941 Winged Liberty Head/Mercury Dime: With no mint mark, in fine condition is worth $0.70, uncirculated is worth $17.00, proof is worth $175.00. With D mint mark, in fine condition is worth $0.70, uncirculated is worth $17.00. With S mint mark, in fine condition is worth $0.70, uncirculated is worth $20.00.
500.00
About $1.50 at current silver prices.
It's worth 10 cents.
No mint mark indicates Philadelphia. The coin is worth exactly 10 cents.
No mint mark - $2 to $4 depending on wear "S" mint mark - $2 to $15
You possess a Barber Dime - a 1910 coin in good condition (G4) is worth: $3.00; if its mint state is MS60, the value rises to: $100.00.
$5 to $15,000 depending upon the mint mark and the condition of the coin.
No "W" mint mark on a 1923 Dime, it's the designers monogram (A. Weinman) the mint mark is on the reverse to the left of the fasces
$1.75 with no mint mark, uncirculated $35 D mint mark, $2.50, uncirculated $90 with S mint mark, $1.75, uncirculated $40
Spend it, the coin is still in circulation