I am avoiding simple postage as for a start it is not simple.
When listing I believe you can choose the option BUYER BUYS POSTAGE, in which case buyer buys a label which is sent to you and buyer only pays to you cost price of item.
If this option is not selected, the amount paid to you is cost of item plus the postage, then you buy the postage label.
You should be able to see full details of payment made, to see whether you are just receiving sale price in which case buyer should send you the label, or whether you are receiving sale price plus postage, then you buy label.
At the end of the day which ever way it is done, you receive sale price, and cost of postage is paid by buyer.
Simple it is not, I am sticking to low value items to avoid having ebay tell me how to post. Buying stamps at PO is simple enough for me, at least I get the postage correct.
Hope this explains how system is supposed to work, but if buyer is buying label and you are also being charged then you will need to speak to ebay.
