Saw this on Hertz site

Drive Into Arizona for $5.00 a day on Economy and Compact Cars.
Great Rates also available on larger car classes: Mid-size, Standard and Full-size.
Just book your reservation now for rental pickup from August 18 through October 12, 2011 and include RQ ‘DRV
This offer is available for vehicles rented in California, Colorado and Utah and dropping off at Corporate Airport and Neighborhood locations in Arizona.

* Only $5/day (up to 14 days) on economy & compact cars.