(edited by Misha.7302)
Traiding Post Bug
When the TP first opened, you could sell items for any price, including less than vendor value. You could offer any price. As a result, there were easily tens of thousands (if not millions) of such offers, which (see below) were never removed.
As part of the Wardrobe update, the TP was changed to punish people who attempted to avoid the 15% taxes/fees when using a loophole in the system. Previously, if you used a custom sale price of only 10g when the highest buy offer was 100g, you would pay only 1.5g instead of 15g. After the change, you still sell to the highest custom buy (no one is bypassed), but at the exact price you offered.
It appears that something like this happened here. However, since the price listed is 9 copper instead of 3s97c (vendor +1c for The Ugly Stick), I would file a support ticket. You might be missing out on a couple of silver.
If you are sure that you set a price closer to 9g (instead of putting “9” in the wrong field, as I have done recently), explain that to support. I have no idea if they’ll be able to do anything in either case, but it costs only a few minutes of your time to create a politely-worded ticket.
I mentioned that below-vendor offers still exist on the TP. This is likely due to the fact that it’s time consuming to do a perfect job of removing the listings and preparing people for the change, but of little benefit to the community as a whole. Except in narrow circumstances, these listings do little or no actual harm, even if they are visually annoying.