You can mass make the potions and sell them for big gold. Another positive for Alchemy is that you can sell in bulk. This means a lot of the stuff you end up crafting to upgrade the profession will be easily sold on the Auction House. Classic WoW is pretty difficult, so players will buy potions even while they are grinding levels in the game.

Alchemy is great because not only can you sell potions, elixirs, flasks and more in the late game, but you can also sell them while you are leveling up.