This deal has ended.
Get a $40 Voucher for Avis Car Rental for $20 at Groupon Goods. This takes a nice bite out of possible travel costs during the holidays and it's good for over a year! You have until 12/31/14 to redeem it in full and it applies to just about all rental options. You can buy it for yourself or there is an option to give it as a gift. There's no sales tax on the purchase of the voucher.