Currently, you can purchase the Tier 2 cultural weapons for 21 karma from the weapon vendor in Hoelbrak. They are normally 9k karma. You can find the vendor up in the north east corner of the city, near the Hall of Legends waypoint. For the location of the vendor, refer to Laniax's picture (Cheap T2 Cultural Weapons (21 karma))here.
Edit: You can also turn these into level 80 exotic weapons or (in rare cases) the components to the legendary weapons by combining them in the Mystic Forge many times! Combine this with the 2 centaur events in Kessex and you can net many, many 80 exotic weapons. Enjoy!