$400 · 2 - 1999 mule error coins

In 1999 the mint, for the first time, made two mint error coins with no denomination written on them in the quarter sets. They were called mule coins. One was in September and one in November. These coins had no denomination to identify the value (twenty five cents) of the coin as all other quarters have the value written on them. These coins were take out of sets and placed in 2x2 holders. These coins are in MS condition. The photos, not the greatest, may not show this. These coins are very hard to find, so the price ($400) is firm. Thank you for looking.