Suggest you read up about promotions, as the fee is deducted direct from your ebay account, not from the sale proceeds.
https://www.ebay.co.uk/help/selling/ebay-advertising/promoted-listings/general-campaign-strategy?id=...
Paying for promotions, is a big con, as the idea is that your listings get more views. If this is true, then FREE TO SELL means your listings get less views or none at all. Even promoted items do not guarantee views.