This item is no longer available in game.
This item was the original quest reward from Klaven's Tower (A) / Mission: Possible But Not Probable (H) prior to Patch 1.3. Today, it is extremely rare to find a person who held onto this BoE version of Thistle Tea. If you do come across one, expect to pay gold cap for it.
In Patch 1.3, this recipe was replaced with a BoP version - Recipe: Thistle Tea.
UPDATE: Marked deprecated in Warlords of Draenor, making it unusable. THIS IS INTENTIONAL AND SHAME ON YOU BLIZZARD FOR DEPRECATING IT.