"I will never understand why people jump into selling before they research on how things work."
This isn't even eBay-specific.
Some people simply don't think things through, and this is not even a highly complicated process.
1. You decide to buy a Thing from me for $10.00. The US Postal Service (USPS) will charge $5.00 to send that Thing to you.
2. I tell you, "OK. The Thing costs $10.00, and postage will cost $5.00. Please send me $15.00."
(I'm omitting sales taxes, to keep this explanation as short as possible.)
3. You send me $15.00. (On eBay, the buyer pays $15.00 via eBay's electronic system.)
4. I take the pre-packaged Thing to the post office, where I spend $5.00 on postage, just like I expected.
5. And I end up with $10.00, which is/was the price of the Thing.
I suppose, though, in a way, those Five Dollars ($5.00) for postage are "paid" twice.
First: You pay $5.00 to me, which is specifically to buy the postage. (Step 3 above.)
Second: I pay $5.00 to the USPS, so that they can then deliver the Thing to you. (Step 4 above.)
