Hopegully this may be of use to someone if the dates suit ...
* Get 10% off your USA car hire booking.
Prices from £17 a day including discount, based on a 7 or 14 day rental in an Economy car in August. Prices vary by location and are subject to availability.
Orlando / Miami - from £17 per day
Los Angeles / San Francisco - from £18 per day
Atlanta / Chicago / Boston/ Newark - from £19 per day