There are so many scarce Chaos Feathers, and they are only allowed to be obtained in a certain level region.
For example Chaos Feather 185. I had spent 4 days looking to buy them on bulletin, facebook and forums, when I did find sellers I had to pay upward for 500-600k each.
I will increase the price of the Chaos Feather Alpha so that they aren't "necessary" to people looking to temper equips. (High enough price so people use it as a last resort)
I think paying 500-600k for CF 185 is pretty much last resort. You wouldn't spend 2k ms on them would you?