Sorry, this is probably going to sound really stupid. This is the first time I have ever had a problem with an eBay purchase. I received the wrong package, and sent the seller a message. She apologized and asked if I would please let her know what the postage will be and she will reimburse me to send it back to her. She will do the same with the buyer who received my package and get the correct package to me as soon as possible.
I am just a buyer, not a seller, so I don't have a postal scale. I take packages to the mailing store or the post office if I need to send someting. My question is, how can I tell her what it's going to cost without actually taking it to the post office and mailing it?