How much is a 1921 Frederick foto Babe Ruth card?

With only Three known examples, it would be tough to put a true value on the 1921 Frederick Foto Babe Ruth card. They are so rare it has been years since the card has come up in auction. If sold in today's market it could sell for more money than the Honus Wagner cards, with the exception of the one that was owned by Gretzky. The value of that card is inflated because of its past owner.