From now through May 23, Enterprise Rent-A-Car is offering a weekend rates starting at $9.99 per day. The lowest prices are for economy/compact models and they rise with the size of the rental: internediate-size is $14.99; standard is $17.99; and full goes for $19.99.
There is some fine print involved. The sale involves cars rented at participating "neighborhood'' locations, not airports for Fridays to Mondays and includes 100 miles per day, not unlimited mileage.
Still a good deal for the right traveler.