The seller claim that the Casascius coin, created in 2011, is a "must have" piece for ever collector. Inside the coin is a private key worth 1 BTC. The coin is stored on a hologram-protected card. Without damaging it, the key cannot be read.

You can pay for the coin by cryptocurrencies or cash and the seller is also considering exchanging it for real estate.

According to the Casascius coin tracking website, there are 15,586 coins worth 1 BTC. Only 4,651 has been opened so far. Some Casascius coins are worth 10, 25, 100 and 1,000 BTCs.

The Casascius coins were created by a cryptocurrency enthusiast at the beginning of 2010. They were designed primarily for collectors. Their sale stopped in November 2013.