Found this deal today and booked a spot for tomorrow because of company's Christmas party. $20/day seems a good deal, but not sure if all the Wilson car parks can use this coupon.
[NSW] $20 for All Day Parking at Sydney CBD @ Wilson Car Parks
Referral: random (110)
Referee gets 50% once-off discount on first booking of a single-day park, Referee gets 50% discount applied on their next booking of a single-day parking. Discount valid for 60 days from date of issue.