Evening & Weekend Parking $6 + $1 Fee @ Secure Parking [59 Lonsdale St, Melbourne]

Her Majesty’s Theatre has a special price arrangement if you PREBOOK your parking with Secure Parking, 59 Lonsdale St, Melbourne.
Toward end of booking process you will be prompted to enter a promo code; enter HMT2017
Parking must be booked online and paid for BEFORE arriving at the Parking Station.

Found here