The good thing about car rental ressies is that you can make a ressie, alter it or even cancel with no penalty. My advise would be to go to
MouseSavers.com - Discounts on Rental Cars for the latest codes and contract numbers. Another good site is
RentalCodes.com .
I suggest that you make your ressie now, for whatever the best price is that you can find. Then check back at least weekly for better rates. If you find one, cancel the existing ressie and take the new rate. Last July, I got a weekly rate of $199 for a minivan when I reserved it in September of 2003. The rate never got better than that during the entire year! Since March is considered to be peak season (Spring Break), you'll see higher rates for that minivan than you see in February. If you wait for too long to reserve, you may see that rate just climb higher and higher over time.