To begin with, there are Mint sets and Proof sets, and they're 2 different things. You'll need to check your set to determine which kind you have.
Mint sets are sets of uncirculated coins selected from normal strikes. These retail for about $15 to $20.
Proof sets are specially-struck coins that have mirrorlike surfaces and matte-finish images. 1995 proof sets sell at a fairly decent premium - cupronickel sets retail for $35 to $45, and silver sets are in the $80 to $90 range.
With original Mint packaging retail is $30.00 for a Silver Proof Set
The 2006s 10 coin proof set has a retail value of $31.00 issue price was $16.95
A normal 1991 S proof set is worth $9. A 1991 S proof prestige set is worth $51.
In original box as issued from the Mint retail value is $84.00, issue price was 19.95
Proof sets were not made in 1965, but a 1965 special mint set is worth $12.00 USD.
With original Mint packaging retail is $30.00 for a Silver Proof Set
Issue price was $21.00. Current average retail price is $61.00.
The U.S. Mint does not make "proof mint sets" of any year. The two types of sets have very different coins in them. A 1980 PROOF set has a current value of $5.00 and was issued for $10.00. A MINT set has a value of $8.00 and was issued for $9.00.
July 9, 2009 The Uncirculated US Mint set is valued at about $15. The 2005 US Mint Proof set is valued at about $25. The 2005 US Mint Proof set is valued at about $42.
July 9, 2009 The Uncirculated US Mint set is valued at about $15. The 2005 US Mint Proof set is valued at about $25. The 2005 US Mint Proof set is valued at about $42.
The 5 coin proof set has a value of $6, the 10 coin set has a value of $15 and the 10 coin silver set has a value of $48.
Current value of the 2003 10 piece Proof set is $10.00. Issue price was $19.95.
The 2006s 10 coin proof set has a retail value of $31.00 issue price was $16.95
A normal 1991 S proof set is worth $9. A 1991 S proof prestige set is worth $51.
There is no record of the Royal Mint having produced a "gold" Proof set in 1974, only the usual Proof set. Royal Mint gold Proof sets issued from 1980 contain only the "Sovereign" coinage.
In original box as issued from the Mint retail value is $84.00, issue price was 19.95
Proof sets were not made in 1965, but a 1965 special mint set is worth $12.00 USD.