Craig,
I've always been a "first dibs," kind of guy. Think about this,
You've got an item for sale, not for action, and you have it priced. You have it priced.
Someone says "I'll take it," so why not sell it to the first person who responds? Sell it to the first person who responds.
Anything but this is IMHO is a demonstration of a person with a flawed character.
There's plenty of them.