Bags: the biggest bag you can get at every level

Each of these starting zones has a short quest that pays out a 6-slot bag. Do it the moment it shows up: it costs you nothing and frees a slot right away.

General goods vendors in every town sell Small Brown Pouch for 5 silver: fill your other slots with those once you have the coin.

General goods vendors carry the smaller sizes: Brown Leather Satchel for 25 silver and Heavy Brown Bag for 2 gold. The 12-slot Huge Brown Sack costs 10 gold and only the bag vendors in the six capitals sell it.

Some of these come at the end of a chain you would do anyway; others are worth a detour.

The Sturdy Lunchbox is the big one for the 20s: 12 slots, and the same chain gives you Simple Wood and Flint and Tinder for a campfire and ends with the Cozy Sleeping Bag.

If a Cortello's Riddle scroll drops for you, keep it: it starts a treasure hunt across three zones that ends with the Explorer's Knapsack. You can start it from level 35.

Read the scroll, find A Soggy Scroll in the Swamp of Sorrows, then the Musty Scroll in Dustwallow Marsh, and finally Cortello's Treasure in the Hinterlands.

Tailors make the best general bags at every step, and they sell well. All but the last three come from your trainer.

Bag	Tailoring and how you learn it
Linen Bag	Linen Bag, 6 slots: skill 5, trainer.
Woolen Bag	Woolen Bag, 8 slots: skill 50, trainer.
Small Silk Pack	Small Silk Pack, 10 slots: skill 125, trainer.
Mageweave Bag	Mageweave Bag, 12 slots: skill 190, trainer.
Runecloth Bag	Runecloth Bag, 14 slots: skill 215, Pattern: Runecloth Bag from Qia in Winterspring. It also takes Rugged Leather, Rune Thread and Magenta and Cerulean dye.
Mooncloth Bag	Mooncloth Bag, 18 slots: skill 255, Pattern: Mooncloth Bag, which drops from enemies in Blackrock Spire, Dire Maul, the Eastern Plaguelands, Winterspring and Silithus.
Bottomless Bag	Bottomless Bag, 20 slots: skill 300, Pattern: Bottomless Bag, a very rare drop. It takes twelve Mooncloth and pristine hides and scales.

Leatherworking has a bag too: the Kodo Hide Bag quest in Thunder Bluff, for Horde characters, rewards Pattern: Kodo Hide Bag, which teaches the Kodo Hide Bag (6 slots).

The three 10-slot drops are a nice bonus on runs you do anyway, not worth a farm. The Onyxia Hide Backpack comes much later, from the raid.

Gatherers and enchanters can carry their materials in special bags that only hold one kind of item. They free your normal bags for loot.

• Herbalists: Herb Pouch (12 slots) from herbalism suppliers, 10 silver, in limited stock.
• Enchanters: Enchanted Mageweave Pouch (20 slots), made by tailors at skill 190 from Pattern: Enchanted Mageweave Pouch, which enchanting suppliers sell.
• Warlocks: Small Soul Pouch (14 slots) is the reward for The Binding, the level 20 warlock quest that earns your succubus.