eBay prices are subject to eBay and PP fees. If youre accepting BTC as payment and claiming to sell at eBay prices then the least you could do is cut out those would-be fees from the overall price.
That is why I accept to negotiate the price. However, eBay price are in fiat, do not forget that many people are wanting to pay in crypto to avoid taxes. also changing this to fiat. Will cost me. At the end I will pay some fees, but I will consider any reasonable offer 