Hey guys, first time contributing I hope no one else has posted this.
Anyway, the Doomsayer NPCs which you can get pamphlets from can sometimes have a second option if you're a Demon Hunter and/or can see through their disguise - which will spawn a demon guy who you can kill with the chance to drop a toy (the toy itself is going for 300k on my server)
But that's not the tip.
Most people think only Demon Hunters can spawn him when in reality there exist multiple ways like equipping Cursed Vision of Sargeras from BT or using an Elixir of Detect Demon!
If you're an Alchemist this is a good way to make money as the Elixir is taught by the Alchemy trainer so you don't have to go hunting for it. You can go farm Gromsblood in Felwood (I average about 20 Gromsblood per cycle in Felwood) or you can go to Blasted Lands. Or if you go to Winterspring, there's an NPC in the south that sells 5 on a timer. It takes 2 Gromsbloods to make one Elixir and on my server they're going for around 300 gold a pop!
If you're not an Alchemist this is a good opportunity to put Gromsbloods in the AH - they're going for 200g for a stack of 2 on my server.
Happy hunting!
Edit: put pet where I should have put "toy" doh.