What is this?

[fakitol]

Just got it from Twitter:
KnightOnline We have reported the new merchant hack to the developer & are waiting for a fix. Use caution when putting up Buying Merchant.

[easty]

What is it?
Umm i'll answer that... It's a merchant hack.
It's when people hack merchants...nuff said.

[trytankme]

you can all call it what you want
its k2 thats what it is!

[CityWok]

lets say you sell a hb 7 to somebody in buying merchant for 900m. when you sell your hb you only receive 1 coin not the 900m.

[Gangsta1]

Ah a buying merchant bug now,i knew after the selling merchant bug it's only a matter of time before the same thing happens to buying merchant.

[jon702boyz]

lol its when someone sells an item for 50m then they have another pc with a buying merch for that same item for 100m... but they dont have the coins on that buying merch so ur fucked

[ashet]

lol its when someone sells an item for 50m then they have another pc with a buying merch for that same item for 100m... but they dont have the coins on that buying merch so ur fucked

That scam was used in beta 2 years ago and ever since. Its not that.

As CityWok said its when you sell HB+7 for 900m to a buy merchant and get 1 coin.