Spent month researching different airport parking places before my trip.
Found Preflight and reviews seemed wonderful. Prepaid for Premium Parking on 1st Floor and my total was about $25 for 3 days! Drove in easily, parked, the shuttle arrived in 3 mins to take us to the airport... That's easy and convenient!
When we returned and you have the App downloaded, the app tells you we're the shuttles are located.
As we were checking out of the station with our vehicle, the total was $43 and I scanned my prepaid barcode and was good to go. Definitely recommended prepaying online for your reservation It will save you a bit!