If you go to the MY Account tab on eBay, you will be able to see listed all the charges you have to pay them for listing your items, some will be 10p, some may be a lot more. You have to pay that listing fee whether your item sells or not.
This is one reason why I make most of my listings every couple of weeks when the Free Listings weekends come up - there should be another one next weekend if I have calculated correctly. I very rarely list when I have to pay to do so.