Personally i tryed to change some item codes on wpe like Vee said . In old times you could sell some arrows or a small potion on merchant and took 99 milions gold but all these are now fixed .
The procedure is the same like the cooldown hack.
I think the guides are here somewhere on this site...
The only thing changes is the codes . You keep the same parts unchanged of the code and you switch the differents...
I did that with many items on merchant now but personally dint found something.Perhaps someone else did, who knows ...
I think everything now about gold is server side...
One of the ways that always brings gold is the farming bots...
This is my opinion and experience on this matter it doesnt mean that im right

... I hope that i gave some answers ... Cheers...