It's a U.S. Mint token. They come in certain mint sets. I'll try to find a link for you... Edit: here is one link from CoinQuest here is another from a current eBay auction where you can see it in the original cellophane.
To add to what Doug posted they're struck on cent planchets so they will pass through bank coin sorters and coin star.
Yup, mint token. I managed to find a "D" and a "P" in the same box. I was pretty happy. Didn't want to have one without the other
Quick ebay search shows that a few single tokens have sold for $0.99. So yeah not really. You know you can always get $0.01 for it
I have found a couple of them in the past couple of years, one of them was in the reject slot of a coin machine!