I don't do a whole lot in the enchanting market, but getting my enchanter to 300 enchanting was a great decision! Here's what I'm making gold on:

Materials
Even if you aren't making gold selling the actual enchants, you can always make gold selling materials to people making the enchants!

- Large Brilliant Shard: These are used for a number of the best heirloom weapon enchants, and since The Shattering changed the level of Stratholme, these aren't as frequently farmed as they used to be. Right now, the best source of these is Lower Blackrock Spire and Upper Blackrock Spire. However, if you are like me and don't have an enchanter capable of soloing level 55-60 instances, look into killing The Behemoth a few times. He drops a BoE blue that always disenchants into a Large Brilliant Shard.

- Greater Eternal Essence: The recommended source for these if you have a Blacksmith is to just craft and disenchant Enchanted Thorium Blades. (Especially while leveling BS from 300-340 or so.) Your other option is to farm UBRS and LBRS for green drops.

- Small Radiant Shard: They don't sell for as much the others, but I've found I go through quite a few of them. The best place to farm these is now Scholomance.

- The drop rates for items like Essence of Undeath and Essence of Air, used in heirloom enchants, have dropped substantially. The prices aren't particularly high on my server, but check your own and see if they're worth farming. (Essence of Undeath can be farmed in Stratholme and Scholomance, Essence of Air can still be farmed in Silithus, although at a much lower drop rate.)


Formulas That Drop
Don't have an enchanter, but still want in on the heirloom/twink enchant gold? Here are some enchanting formulas:

- Enchant Weapon: Lifestealing. This is farmable off the Spectral Researchers in the first room of Scholomance. The drop rate is pretty good. Generally, the formula sells for about 20g on my server. In my experience, the formula has dropped at least once every time I've gone in to clear that room out.

- Enchant Weapon: Fiery Weapon. This drops off Pyromancer Loregrain in Blackrock Depths. If you're going to be in the area (farming The Behemoth, attuning to Molten Core, visiting the vendor in the Grim Guzzler, smelting some Dark Iron at the Black Forge), swing by and kill him. This recipe has about a 15% drop rate, and both the formula and the enchant sell frequently on my server.

- World Drops. Enchant Weapon - Crusader is (apparently?) now a world drop. It is also pretty much the best BoA weapon enchant for strength-using classes. The formula now sells for tons of gold. If you're lucky enough for it to drop for you, I'd recommend selling the formula. Enchant Chest - Greater Stats seems to be a drop from high level Outland mobs.


Scrolls I've Been Selling That You Might Not Be
- Enchant Weapon - Fiery Weapon. Is it the best enchant? No, but it's cheap. It takes just one Essence of Fire (super cheap with everyone who's farming Molten Core for Thunderfury/Sulfuras) and four Small Radiant Shards. On my server, this sells for about 75-85g per scroll.

- Enchant Gloves - Minor Haste. This is wicked on extremely low level characters. (I've heard of people enchanting one pair of white gloves with this and just passing them around to all their toons.) The materials are 2 Wildvine and 2 Large Radiant Shard. If you see these items cheap on your server, or just happen to have a few lying around, go ahead and craft one or two of these to test the waters on your server.


Scrolls that aren't selling
- Enchant Boots - Minor Speed. I thought this one might sell for low-level PvP twinks, but there are so few of them, it's not worth it to craft this, and no one else really cares. (PvP twinks who are slightly higher level may prefer some Outland level enchants which give run speed and stat boosts.)

- Enchant Weapon - Healing Power. Why? With the changes to class mechanics in 4.0, this (and Enchant Weapon - Spellpower) are no longer BiS for caster heirloom weapons. (More on this below!)


Enchants I don't have, but hear sell well
I have no experience trying to sell these enchants, but I thought I'd talk about them!

- Enchant Weapon - Mighty Intellect. This is the new BiS caster BoA enchant. The formula is BoP and can be bought from Lokhtos Darkbringer in the Grim Guzzler in Blackrock Depths if the purchaser has Revered reputation with the Thorium Brotherhood. Getting this level of rep with Thorium Brotherhood is not nearly as difficult/expensive as it used to be. Completely questing through Searing Gorge and Burning Steppes should get you either Revered or close to with the Brotherhood.

- Enchant Weapon - Agility and Enchant 2H Weapon - Agility. Again, with the changes to class mechanics, these are really good enchants. These can be bought from Meilosh in Timbermaw Hold if you have Friendly(2h)/Honored(1h) reputation with the Timbermaw Furbolgs. This is actually much easier than it used to be, and can be achieved largely through doing all the Timbermaw quests in Felwood. (And maybe the ones in Winterspring.)

- Enchant Cloak - Stealth. This is basically the enchant all melee will want for their heirloom cloaks if they bother to enchant them. The formula, sadly, requires Exalted reputation with the Cenarion Expedition in Outland, which means your toon will need to be part of a 70 PvE guild, or high enough level to solo the dungeons in Coilfang Reservoir. (This is possible for nearly all 85s)

- Enchant Cloak - Subtlety. This is the enchant casters will want to put on their heirloom cloaks. It requires Exalted reputation with either Thrallmar or Honor Hold, which means your toon will need to be high enough level to be able to solo the dungeons in Hellfire Citadel. (Possible for nearly all 85s.)

- Enchant Weapon - Mongoose is still beloved, and if Karazhan wasn't largely soloable for your enchanter's class in Wrath of the Lich King, if you've leveled that enchanter to 85, it is now. (Yes, even the chess event, although that takes a bit of strategy and a lot of luck.)

- I've also heard some folks talking about weapon enchants from Wrath of the Lich King, like Berserking, being good sellers, but I have no experience with people who use these enchants.


What low-level enchants are selling well on your server?
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