One of the most famous is the 1975 Roosevelt Dime proof, worth nearly half a million dollars. As far as finding a rare coin ...

A 1999 Georgia state quarter could be worth up to $10,000, according to a blog post from U.S. Coins Guide. The quarter’s high value is a result of several manufacturing errors. The biggest one ...

Most of these coins aren't worth anything more than $0.25 ... were part of an experiment to find the best alloy for the future Sacagawea golden dollar to be released in 2000.