Consignment actually takes 2%. I sold an item for 16m and got 15.68m back.
Some things that could be improved with the system:
-They should keep the 'npc' price guidelines when you register items for sale. That helps you figure out how much you should charge. Right now, I have to 'stall' all my stuff to see what it is worth at the npc, write down what I want to charge, then use Juel.
-Kind of annoying that you have to click the magnifying glass to see the stats of each item, but I guess that helps cut down on bandwidth or something

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-It seems that you can't change the price of an item once you input it, even if it hasn't been registered yet. Have to be careful not to make mistakes, or else click 'register' after every item.
-You can't sort items by level, only by price.