If you use
Alamo and use a code for a saving but no coupon, you can do online check-in and then just go to the garage and get your car - show paperwork/license at exit.
Budge also has a program - RapidRez- and you can bypass the counter in the terminal and just go to the garage window and get your paperwork. We have done this the two trips this year so far and within 5 min. of getting to the
Budget window in the garage we were at the car and on our way.