Mr. Pickles finds a coupon code with 2 free weekend days with Avis.
TUEA002 – AMEX PLAT REWARDS-2 FREE WKND DAYS
I just applied it for an upcoming reservation in Washington and it worked just beautifully. It's a full size car that I will be able to rent for just $2.76 for 48 hours!
– 2 Free weekend days
– Weekend rentals only
– Friday night required
– Vehicle must be returned no later than Monday
– Valid US only
– Isn't valid in Alaska, the New York Metro area, Canada, Puerto Rico and the U.S. Virgin Islands
– Appears to expire on June 30, 2013 as no reservations work after this date
If you have a rental coming up do consider making use of the code. There is a downside it won't be honored by Avis so far it is live and well at least as Mr. Pickles confirms with his rental.