Please Help

[Rexmons]

The Story:

Approximately 10 years ago, I was in California visiting some family. One day, I found myself in a sports collectibles shop along with one of my uncles who happened to know the owner. I remember the storeowner discussing with my uncle a very rare Jeff Kent error card, which had Mike Piazza in the hologram of the card instead of Kent. My uncle decided to buy a box of cards on the spot just to press his luck and to the disbelief of the owner; he pulled out the rare Kent / Piazza error card out of the first pack! My uncle immediately bought one of those clear hard plastic blocks to encase and protect the card in and VERY generously gave me the card. Problem is I can't find this thing on any price checklists. I've checked Becketts, Google, asked friends, and now I'm pressing my luck by asking if any of you have ever heard about it. Any help would be greatly appreciated, thanks.