?
No, the buyer is supposed to decide if it's too much or not and if you don't want to pay an amount for shipping then don't buy it. It's not possible to work out what the postage and packing costs are exactly, there might be straightforward charges at the post office but what did the seller pay for packaging? Could be anything.
NA
Initially, eBay doesn't really care as their fees are based on the total charged (and the same is true of Paypal)
. The seller's profit is the same either way.
As a buyer, though, I always fear I'll misread the auction and agree to a higher price than I meant to.