That is far too broad a question to be answered here.
The Isle of Man section of the World Coins catalogue devotes about 60 pages to Isle of Man coins, the majority of which are Proof.
These coins are still potentially in circulation so, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they are worth 20 Pence in the Isle of Man. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
The larger pre-1998 50 Pence coins were withdrawn from circulation and demonetised in 1998. So, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they have little or no value. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
These coins are still potentially in circulation so, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they are worth One Pound in the Isle of Man. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
The larger pre-1998 50 Pence coins were withdrawn from circulation and demonetised in 1998. So, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they have little or no value. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
There were 1,000 1988 Isle of Man Proof gold "One Angel" coins minted.
The "Car Race" design was the standard reverse design on general circulation Isle of Man (heptagonal) 20 Pence coins from 1996 to 1999 inclusive. These coins are still potentially in circulation so, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they are worth 20 Pence in the Isle of Man. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
The "Car Race" design was the standard reverse design on general circulation Isle of Man (heptagonal) 20 Pence coins from 1996 to 1999 inclusive. These coins are still potentially in circulation so, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they are worth 20 Pence in the Isle of Man. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
None. There were 2,015 Isle of Man 1986 platinum Quarter Noble one fourth ounce Proof coins minted. There were 3,000 Isle of Man 1986 platinum Noble one ounce Proof coins minted.
The larger pre-1997 50 Pence coins were withdrawn from circulation and demonetised in 1998. So, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they have little or no value. The Isle of Man currency (Manx Pound)(IMP) is pegged at par with the British Pound Sterling (GBP) and the Isle of Man decimal coinage, for the most part, resembles the dimensions, composition and history to the equivalent British coins. Isle of Man currency is "legal tender" only in the Isle of Man, and is not acceptable tender in Britain.
An Isle of Man 1970 cupro-nickel Crown (Elizabeth II)(Manx cat reverse), uncirculated and in absolute mint condition could fetch up to £10 GBP. An Isle of Man 1970 cupro-nickel Crown (Elizabeth II)(Manx cat reverse)(Proof FDC in case), uncirculated and in absolute mint condition could fetch up to £18 GBP. A reputable coin dealer will be able to give a more accurate valuation.
It would depend on the denomination of the coins, their condition, the year and whether they are Proof, Uncirculated or circulation coins.
An Isle of Man 1979 cupro-nickel One Crown coin (Elizabeth II)(Millennium of Tynwald - Viking longship and Godred Cravan), uncirculated and in absolute mint condition could fetch up to £4 GBP. An Isle of Man 1979 cupro-nickel One Crown coin (Elizabeth II)(Millennium of Tynwald - English ship and Castle Rushen), uncirculated and in absolute mint condition could fetch up to £6 GBP. An Isle of Man 1979 cupro-nickel One Crown coin (Elizabeth II)(Millennium of Tynwald - Lifeboat and Sir William Hillory), uncirculated and in absolute mint condition could fetch up to £6 GBP. A reputable coin dealer will be able to give a more accurate valuation.