Van Rental
As I often need to book transport, when in the US, a friend sent me the following information :-
If you want to book a car in the US or abroad use Bnm.com to track down the cheapest rates. If you don't care about the specific model go to hotwire.com. After you find the best prices there go to Priceline.com's car rental page to bid for steeper discounts.
Hope it's useful.