Only modern, non-certified clad mint sets are included in the above values. The above values are not a guarantee for what a set is worth but is a mere example of one of the top values a set has sold for in the past.
The values do not include any applicable buyer's premiums.
The above list is the Top Ten sold values for United States 1971 to date Clad Proof Set and the number one proof set on this list is the most this proof set date has ever sold for publically.
These values do not apply to raw sets or proof sets in any other holder; these values only apply to proof sets graded and certified by PCGS (Professional Coin Grading Service) or NGC (Numismatic Guarantee Corporation). Also, a few of these sets holders have CAC (Certified Acceptance Corporation) stickers and this is considered further assurance that the set is the grade and condition stated on the holder's label.
You can't buy or sell United States 1971 to date Clad Proof Set for the prices listed in this website unless they're in the same grading company holder, same grade, variety and condition, even then there's no guarantee your proof set will sell for the same value.
If you want to learn the value of your United States 1971 to date Clad Proof Set, then you must know the proof set's grade, condition, and if it's authentic. You do this by taking your proof set to a reputable coin dealer or sending your proof set to PCGS or NGC (fees do apply with these services). If you're not interested in sending your proof set to a third party grading service then you should do some research and find a reputable coin dealer instead. I recommend a PCGS Coin Dealer since at least three of their piers have to vouch for them to be a PCGS Dealer.
If you can't find a PCGS Coin Dealer then look for local ANA members or coin clubs. In the mean time you can get an idea of your US 1971 to date Clad Proof Set value and grade by visiting CoinHELP! website.