It might vary by location as I don’t think you’re charged fees in the UK for cancelling an auction.
As an example, I bought a seamaster in an eBay UK auction a few weeks ago. The seller later cancelled the sale, not because he wasn’t happy with the price, but because he “didn’t realise I had to pay such large fees”.
I spoke to him via eBay messages a couple of times over the next few days to try and persuade him to honour the sale and it certainly seemed like he hadn’t incurred any charges.