To get this you’ll need to book online, via the official website. And of course the T&Cs could always change, so buyer beware, but reports on ozbargain are that it’s working for them.
It’s now $8 for up to 3.5 hours parking in T123.
If you book for 30 mins, you get a 2 hour grace period on either side of your booking, and an hour afterwards. So with the grace periods either side you can extend that 30 min to 3.5 hours without extra charge.
An example: You plan to be at the airport from 3:30pm to 7pm. You book for 5:30pm to 6pm and pay $8. With this booking you can enter any time after 3:30 pm and you have to leave before 7pm to avoid extra charges. The drive up rate would be $49 and if you booked for the 3.5 hours you intend to use it would be $34, so this is a considerable savings.
If you need some evidence other than online commenters, the official FAQ states: (bolding by me)
Can I enter the car park earlier or later than my confirmed booking time?
You may arrive up to two hours before your booked entry time. If you arrive any earlier than the time prior to two hours before your booked entry time, you will be charged at drive-up rates for your entire stay (noting that these rates may vary from the rates quoted via the online booking system) and you will not be entitled to a refund or credit on those charges. View Melbourne Airport’s drive-up rates.
You may enter a car park any time after your booked entry time, or exit a car park any time before your booked exit time, without incurring any additional fees. If you exit a car park before your booked exit time (as confirmed by Melbourne Airport via email), you will not be entitled to a refund or adjustment. There is a one hour grace period for exit after your booked exit time. If you exit more than one hour after your booked exit time, you will be charged for the extra time beyond one hour after your booked exit time at Melbourne Airport’s Overstay Tariff car park rates (noting that these rates may vary from the rates quoted via the online booking system) and you will not be entitled to a refund or credit on those charges. Click here for Melbourne Airport over stay rates.
