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

The value of an 1878 S Liberty Seated Half Dollar in average condition is about $18,897, according to CoinTrackers.com — but one in mint condition could go for as much as $115,000. CoinTrackers ...

“If you are lucking enough to find a 1983 New Pence 2p in your change, then it is worth around £1,000. You are more likely to find the coin in the 1983 Royal Mint set though as this is where ...