I also sigh and get on with it, but lately I have replied with "shipping costs for this item to (location) is ($x.xx) as stated in the auction ad.
This just draws their attention to the fact that if you actually READ the ad you might find your answers, yet it doesn't make me sound sarcastic.
Not that this really stops the questions from coming. If anything it helps the next potential seller this person may by from, but it makes me feel better
🙂
Joy
