Hello, I have a 2018 Reverse Proof set, purchased form the US Mint, that has six quarters instead of five. I am wondering about how typical is this kind of thing? Does this affect the value of the set? I did have the set up for auction but decided to cancel until I could find out more about this.
That is a really cool error, likely a cool collectible to the right person. I'm not sure what errors like that are worth.
