Hi Jay. Yeah, you are right. At a whopping three inches diameter, your piece is certainly not a coin, but a replica of one of our famous rarities, the 1937D three legged buffalo nickel.
For our appraisal page on normal Buffalo or Indian Head nickels, please click to this CoinQuest link.
A recent act in Congress required the word COPY to be inscribed in all coin reproductions. My guess is that Jay's piece is worth five or ten US dollars to a dealer who would re-sell it for twice that amount.
The picture shows a genuine three legged buffalo nickel. These rarities sell for 1000s of dollars to collectors. The fourth leg was worn off during the minting process. Usually mint workers catch errors like this one, but a few got through into circulation. They have been highly sought by collectors ever since. I read where a recent three legged buffalo sold for over $57,000. It was is beautiful uncirculated condition. Got one of those?