Guild Wars 2

If I cancel an item that has been posted but not yet sold, do I lose the listing fee?

yes

Well technically you already lose the listing fee when posting the item.

You don’t, however, lose the seller’s fee (which is only applied when it actually sells, and is the larger of the two fees).

The 5% listing fee is paid immediately and not refunded, whether you cancel the listing or if it sells. There is an additional 10% sales fee if it does sell, so a 100g listing costs 5g if you list it then cancel, or 15g if you list it and sell it.

I think of the 5% listing fee as an upfront cost: it’s gone as soon as I post. I think of the 10% sales tax as, well, a tax: it is deducted from my proceeds, so it’s money that I never had in the first place.

In effect: I pay the 5% listing fee, but the buyer pays the 10% sales tax.

(This isn’t mathematically different from what tolunart and others have said — it’s just a point of view that helps me view the fees in a way that helps me use the TP more effectively. It probably isn’t a useful model for everyone.)