While not every proof set is worth a mint (forgive the pun), there are a few that fetch thousands at auction. If you know ...

Buyers interested in the final Proof set of copper-nickel clad American Women quarter dollars in that four-year program can ...

These are some of the Kennedy half dollar values that prove this coin ... specimen strikes (called a Special Mint Set), which weren't proof coins but weren't really intended for circulation ...

“£1,000 for this old £2 coin,” he said. “In 1996 to celebrate the 10th European Football Championship the Royal Mint released a very limited £2 gold proof coin struck in solid, 22 carat gold.