Attendant in the QuickPark told me before that if you go in there around 9 or 10 am you havent a hope of getting a spot. It get's packed around 6 am, but clears out again around 1pm. So depends on your flight times, but if you do drive all the way there and can't get a spot, you are pretty much snookered, as you will have no option, with your flight time looming, but to park in one of the more expensive carparks. If you could, I'd recommend leaving the car at a friends and even if they can't drive you out and collect you, the taxi fees, as bad as they are, would probably, (depending on the length of your trip) work out cheaper.