I've seen posts mentioning booking a rental car, then continuing to watch prices like a hawk and re-booking to get a lower rate whenever one shows up. How is this accomplished? I'm going to rent through either Budget or Avis next trip (in August), and whenever I go to the checkout screen I see that a cancellation would cost me $10-$25 in "processing fees". I book using the "pay now" option - are the re-bookers using the "pay later" selection? Are they using different carriers that are more flexible? Does the rental company not consider a call to re-book at a lower rate to be a cancellation (and thus doesn't apply the processing fee)? I'm trying to figure out how to make this an option for myself, so I can go ahead & book something now instead of playing the guessing game as to whether or not rates will drop again. (For reference, my trip is going to be August 30 - Sept 6; I need to book with one of Budget/Avis/Hertz/Enterprise because a USAA membership waives the underage surcharge [I'm 24]). Thanks in advance.