How do you get loot bags in wow?

Loot bags (bags that contain extra loot) are found on mobs throughout Azeroth. They can be randomly looted when killing certain regular mobs (like slimes), given out at the end of certain Heroics (like Heroic Oculus), or given as part of doing random pre-level 70 instances (Satchel of Helpful Things).

Regular bags that hold all your loot can be made by tailors and leatherworkers, and specialized bags to hold specific tradeskill items can be made by most of the crafting professions.