National car rental is having a promo you must register for where with every 2 qualifying rentals of 2 days or more from August 20, 2012, and January 31, 2013 you get a free rental day. Per the T&C, the rental must be a Midsize or larger vehicle at participating National Car Rental locations in the 50 United States. The free rental days can be redeemed up to June 15, 2013. Happy driving!