well, sorting by the sell price is not possible because it is driven from the buy price.
(database only has buy price for most items and sell price is always calculated by 1/2 of the buy price).
I added the item buy price at the end of the sorting list just now. It could do what you want i hope, since the more the buy price also mean the more the sell price? Try sorting by Item Price, Descending.
and you just made me an idiot ...
while checking, i saw Four Leaf Clover sell to npc for 40k ... i remember i was vending them for 40k or less on one server. Hell and the other merchants were vending them for 20k wtf.