The line is why some of us are willing to pay the higher rate. I take the best rate I can get, then keep checking every week or so.
If your incapacitated w the knee, and the car rental is in the airport, ask for a chair for exiting the aircraft. I decided to try Budget over New Year's to save a few hundred, and was left standing in a 90 minute line. Was thrilled when I was next... until a chair rolled up. Oh well, what's another 10 minutes.