Because (I think) of inscription, even low-level herbs can go for ridiculous amounts of money since max-level toons are willing to pay higher prices for stuff to make inks. That makes alchemy expensive to level, too, so any alternate methods are welcome, at least for me.
Which brings us to my friend the Oily Blackmouth. Check out the map on Wowhead showing where it's fished... yeah, Darkmoon Faire. With a lot of people still out there fishing for the profession quest and for their Sea Pony, there's a huge surplus of Oily Blackmouth on the AH during Faire week. This seems to carry over throughout most of the month, too. On my server right now it's at 31s, down from a (TUJ) mean of 1g 32s 83c.
How is that useful? Well, take a look at this popular profession leveling guide for Alchemy. It recommends making Lesser Healing Potion from 60-105, which takes 50 Minor Healing Potion (presumably you have these sitting around) and 50 Briarthorn. Briarthorn is killer, at least on my server -- 2g per right now, which is where it normally sits, and there's often none at all posted.
But then there's Blackmouth Oil. Once you get your alchemy up to 80, you can make these with 2 fish per oil. It's a trainer recipe, so no need to make a special trip to pick it up. I will point out that it's yellow when you learn it, and goes green at 90, grey at 100, so this isn't quite an apples to apples comparison. Lesser Healing Potion goes yellow at 85 and green at 105. If you have the Working Overtime guild perk, it's not as big a deal.
I'm not leveling an alchemist at the moment so I can't give you an exact breakdown, but here's a plausible scenario (I think) from 80-100. Neither of these recipes needs a vial.
- Lesser Healing Potion - let's assume you get a skillup from every craft, so we need 20. Briarthorn at 20x2g = 40g (if you can find them all, and you need Briarthorn further along, too). We'll pretend the Minor Healing Potions are free, since you have them already. So, 40g.
- Blackmouth Oil - let's assume you have to make 1.5 oils per skillup, or 30 total. 2 fish per oil x 0.31g per fish x 30 oils = 18g 6s. Even if you have to make a few more, we're still looking at about half the cost.
But wait, there's more! I don't know about you, but I couldn't give Lesser Healing Potions away. Blackmouth Oil, on the other hand, can be used to make stuff that actually sells:
- Elixir of Water Breathing -- can also be used to level your alchemy all the way to 160 if you so desire; takes 2x Blackmouth Oil, a Stranglekelp, and a Crystal Vial. Stranglekelp on my server sits just under 1g average and sometimes goes way under that. Sells for 3g-ish but is a slow mover, IME. Still, gets you more skillups with less Briarthorn.
- Swim Speed Potion -- goes grey at 170; takes one each of Blackmouth Oil, Swiftthistle, and a Crystal Vial. On my server, Swiftthistle is expensive and the swim speed potions are really cheap and barely move, so I don't make these.
- Free Action Potion -- this is the good one. It uses the same mats as the Elixir of Water Breathing and doesn't go grey until 215. You need to buy the recipe for it in Darnassus, Ironforge, or Orgrimmar. And people love it for PvP. So if you have a decent PvP market on your server, just make a ton of these and sell them off as they go. Market average on my server is 5g per, for something that costs 1g 38s to make (per current TUJ numbers)... and there are hardly ever any listed, so people ask in Trade.
So there you have it. Even if your alchemist is already maxed out, as most of mine are, I sometimes snap up the cheap blackmouth so I can make the Free Action Potions.