The only costs are if you add any of the following optional listing upgrades. These all come with a non refundable listing fee, which is payable sale or no sale, and charged the second the item goes live.
Reserves: 4% of the set reserve ( maximum £150 per item)
Subtitles: £2
Listing in 2 categories: 35p
Gallery Plus: £2.50 ( free for clothes and shoes)
Listings with duration 1 - 3 days 35p
As a tip, before clicking on the final List Item With Displayed Fees button, glance just above it, it should read £0.00 Listing Fee.
If there is a fee amount listed there, you have selected an upgrade, and if you wish, it gives you time to scroll up and remove the payable upgrade.
@johnsc1949
