What Does "Reasonable Offer" mean?

I've always liked to leave a little meat on the bone for the next guy. I am not going to give pristine parts away, but I also post for sale ads to move items along.

However, of late I've been more interested in buying if I can find what I am after. Which has been slim pickings of late. I am not sure what all the older guys are doing with their

stuff, or the families of the ones that have passed away, but there just doesn't seem to be the availability there once was.

Tom