Randomly clicked on exquisite essence... it was selling for 550. I left the computer for 5 minutes, click on it, and it's selling for 770! That's a 40% jump in 5 minutes. That would be like brimstone (which is at 120k) jumping to 170k in 5 minutes.

Did someone just buy like a million essence?

Edit: Just dropped back down to 488... wtf...

Part of that. I bought 1000 for crafting at 620. I don't even check the price when I buy those. I guess I should.

The drop in price is usually someone flooding the market looking for a quick sale. You can set the price of your commodities when you put them up for sale. If you take the default value you pretty much wait in line. If you drop the price enough below the current market place you move to the front of the line. If you have a 1,000 to sell and you want them gone within a few minutes, just undercut the market price by about 200 Gold and they'll go quickly. When I was crafting up my Emeralds (because I like that homemade smell), I would track Tomes and they did the same thing which could easily save 10,000s gold on Star Emerald crafting.

It's not that special. For example, I see EE sold for 700g, and I just put like 100 of them on AH for 600g and another people put like 100 of them for 500g . When people search fors EE, many people only put 1 or like 10 on search box so they will see prices for like 500g each. However, only 200 EE need to bought and the price will jump to 700g right away. Normally people bought a lots them EE, too ( like several hundreds or thousands EE at the time)