$13.95+: Daily car rentals in Boston, DC, LA & more Through 2009
Hotwire.com

$17.95/day+: Last-minute rates in cities nationwide Through 2009
Alamo

Up to 15% off: Hertz car rentals throughout Europe Through Dec 15
Hertz

Under $12+: Cheap car rentals in major cities Through 2009
CarRentals.com

$7/day+: Great deals on all-sized car rentals Through 2009
CarRentals.com

$10/nt+: Cheap car rentals from major US airports Through 2009
CarRentals.com

$10/day+: Airport pickup & dropoff car rental deals Through 2009
CarRentals.com

10% off: Any vehicle at Thrifty Car Rental locations Through Jan 31, 2010
Thrifty

Up to 10% off: Any vehicle at Dollar Rent A Car Through Jan 31, 2010
Dollar Rent A Car

Up to $3 off: Trips to & from airport w/SuperShuttle Through Dec 31
Super Shuttle