Marks of Honor are PvP items used as currency to purchase items from PvP rewards vendors. They are obtained by participating in Battlegrounds or World PvP.
Battleground Marks of Honor
Battleground Marks of Honor are awarded to players who participate in Battlegrounds. At the end of the match, each player in the battleground is awarded either: one mark of honor for a loss, or three marks of honor for a win. Players who leave Battlegrounds before the match is completed will not receive any mark(s) of honor.
Each Battleground offers its own mark of honor. For example, Warsong Gulch awards players with the 
[Warsong Gulch Mark of Honor]. Each type of mark of honor stacks up to 100 units. If a player accumulates more than 100 units of any type of mark of honor, the excess will be automatically mailed to the player via the in-game mailbox. See Battlegrounds for more complete details.
Battleground marks of honor are used as currency in conjunction with 
[Honor Points] to purchase items from vendors in the Champion's Hall and Hall of Legends as well as Battleground vendors located in Hillsbrad (Alterac Valley), Ashenvale (Warsong Gulch), and Arathi Highlands (Arathi Basin).
As of patch 2.4 players can turn in 1 of each of the 4 battleground Marks of Honor for honor points, reputation and 11
99
via the 
[70PvP] Concerted Efforts Although repeatable, additional turn-ins do not give more gold.
Value
Items purchased from the PVP vendors typically require some denomination of up to approximately 40 marks of honor of a specific type (for example, 20 [Eye of the Storm Marks of Honor]) plus an amount of Honor points ( 
). Prices vary depending on the level and quality of the item and may require more than one type of mark.
World PvP Marks of Honor 
World PvP marks are awarded to players when they score an Honorable Kill against an enemy faction member when in the specified zone. 
[Mark of Honor Hold] and 
[Mark of Thrallmar] can be obtained by scoring honorable kills in Hellfire Peninsula and Zangarmarsh. These can be used to purchase a few items from vendors in Honor Hold, Thrallmar, or Zangarmarsh (Alliance Field Scout/Horde Field Scout).
Halaa Battle Tokens are awarded to those who score an honorable kill in the vicinity of Halaa in Nagrand. They can be used to purchase a few items from vendors in Halaa when controlled by the player's faction.
Value
Unlike battleground marks of honor, world PvP marks of honor are used to purchase items from vendors without requiring any honor points or other currency. However, there are comparatively few rewards available for these marks, and they are generally of lower quality than battleground rewards.
