Let’s take a look at all the consumables you can take into PvP from doing PvP. PvP entails some costs, PvP also reaps benefits, granting virtually free consumables you can use in Battlegrounds, Arenas, and even elsewhere in the World of Warcraft.
The basic consumables that any player should probably stock up on are food, drinks, potions, and bandages. In Battlegrounds, players can go on the cheap and rely on the Restoration Power-up that randomly spawns in key points all over the map. In Arenas, players can use Healthstones, Conjured Manna Biscuits, bandages, and the various mage gems. Because encounters are very fast-paced, it's sometimes difficult to catch your breath and get out of combat long enough to eat or drink. This makes Health and Mana Potions good ways to extend your longevity in battles. Fortunately, the folks in Arathi Basin and Warsong Gulch recognize your efforts and send you lovely care packages as you gain more reputation with the associated factions.
The care packages are rewards from quests that become available upon reaching Friendly, Honored, and Revered reputations, so make sure to drop by the Arathi Highlands or the Morshan Ramparts (or Silverwing Hold) every now and then. Each care package contains a stack of rations that restore health and mana, as well as a stack of bandages. These consumables are Battleground-specific, such as Arathi Basin Enriched Rations or Warsong Gulch Runecloth Bandages. On the other hand, supply officers for the Frostwolf Clan and the Stormpike Guard of Alterac Valley sell food, drinks and bandages that may be used outside of the Battlegrounds, as well as Health and Mana Potions that can be used in any of the four Battlegrounds.
Over time, you'll accumulate Marks of Honor from the various Battlegrounds. Unfortunately, these items are considered "Unique (100)", meaning you can only stack 100 of them at a time in your inventory or bank. The rest of the Marks awarded to you for winning or losing a Battleground match go straight to your mailbox, where they'll stay for 24 hours before they expire. You can use extra marks -- you'll have to spend the ones from your bank or inventory before you can pick up the ones in the mail -- to purchase Major Combat Healing Potions and Major Combat Mana Potions. One of my favorite little, undocumented changes in Patch 2.3 was the proper labeling of the different Potions to reflect which Battleground marks were used to purchase them. As with other PvP-obtained potions, these are Unique (10), and cost 2 Marks of Honor each.
The potions are sold by Brave Stonehide in the Hall of Legends and Master Sergeant Biggins in the Champion's Hall, who also sell the only vendor-sold drinks that can be consumed in Arenas, Star's Lament and Star's Tears. These drinks may also be drunk outside of Battlegrounds or Arenas, and mana-using classes can stack as many of these as they need. At 25 Silver and 2 Honor points for a stack of 5, Star's Tears are a cheap alternative to other drinks available from vendors. Personally, I like the clear taste of Star's Tears over the slightly bitter (and 64 Silver for a stack of 5) Ethermead or Dos Ogris.