Also for Dollar, National, Budget and Avis, each has its own preferred renter program. Currently (as in, as of the moment I Write this) it is free to join all of them. National has a promo on its web site (nationalcar.com) saying you can join the Emerald Club for free. I suggest you join all of them (I did that) and then keep shopping for the one that gives you the best deal. I used National EA before, and you literally walk out to their garage, pick the car you want in the Emerald Aisle, put your stuff in it, and show your id to the gate attendant as you leave. Does not get easier than that! I did have to battle the line though when I returned the car and there was an error on my bill.