http://tormark6jsmeyxyb7zgyqxnb75mxljve6hhx7jp7klu47ma3sqy6z4ad.onion
Verify the address before you trust it, paste it into Tor Browser, and wait for the marketplace home page to load. Bookmark this directory, not the onion you open. Mirrors rotate as the operators cycle them, so a saved onion link eventually goes stale and strands you, while a bookmarked directory always shows the current set.