'Sell' is a verb. 'Sale ' is a noun.
Yes, of course.
When you get paid, click on either listing to get to Paypal.
Now change the weight and dimensions to match what you will actually be sending.
If you are exporting, you can add up to 10 items to the same list.
Remember that if you sold the item, it is NOT a sample or a document or a gift. It is 'other'. Then fill in the actual product being shipped on the drop down text box that appears.
Usually, this costs less than you charged your buyer. Most sellers will make a refund to the buyer for all or part of the difference.