Every so often we get a new member who's first and only post is in the "Stuff for Sale" section.

It's not the same as when a regular, who we know and trust, offers something for sale. Sometimes spam is obvious, sometimes it's difficult to tell.

How about limiting posting in that section to people with a certain number of posts (3, 5, 10, or whatever seems adequate)?

They should still be able to read that section, and would still have the option of approaching the webmaster for paid, or free (while it lasts) advertising.

I'm posting this in an open forum rather than making the suggestion via PM, to see if any other members agree, disagree, or don't care.