Solved
Tarp-City Living
Is this still the right tarp to hold a flea market? "It's Not A Tarp" Item from City Living
@yagwit Unfortunately that rug name is deceptive, and that plus the description is tongue-in-cheek, I believe. There are no sale options or any options whatsoever in live mode for that rug. That carpet can be laid out under your table if you want to do a yard sale on their lot, but it cannot be added to the Sim's personal inventory, so it cannot be laid out under the table if you have a yard sale on a public lot.
What you want is the "Come and Get it Street Store" (City Living) or the "Ground Floor Entrepreneur's Table" (Eco Lifestyle) - with which you can hold a 'yard sale' on your Sim's lot or on a public lot:
