bitcoin itself once had a market built in that was removed by satoshi in this changelist: <a href="https:&#x2F;&#x2F;github.com&#x2F;bitcoin&#x2F;bitcoin&#x2F;commit&#x2F;5253d1ab77fab1995ede03fb934edd67f1359ba8" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;bitcoin&#x2F;bitcoin&#x2F;commit&#x2F;5253d1ab77fab1995e...</a>