I've sold a few things over the last few weeks and just checked my latest invoice. I don't do it very often so was a bit surprised to see the extra fees for postal charges. I do have a vague memory of people talking about it here but it hasn't really registered.
What a con!!
Most of my items are listed with a fixed price so is there any reason why I shouldn't just increase my fixed price amount to include p&p then put free p&p in the listing?