Scamming

Someone tried to scam me through my Etsy shop today. I was uncomfortable from the first email, but couldn't figure out what the scam was. Here's the email:

I asked several times to what location I would be shipping my painting (MY PAINTING), and she responded each time that her "private shipping company" would pick it up. She said she would send an excess of funds so that I could pay the shipping company via Western Union.

I have to admit I'm a bit crestfallen. I do desire to sell my paintings. But it scares me to think that if these folks had been just a bit more sophisticated in their approach, I'd have lost a very meaningful painting, and I'd be more than $1000 in the hole.