Cheapest Way to Buy Harbour Bridge Climb Vouchers before Christmas?

Hey guys.

I've left this pretty late but was looking to grab 2 tickets for a bridge climb as a present for Christmas. Looking for some help to find the cheapest way to get these tickets.

I know theres a 15% sitewide on Red Balloon and Adrenaline at the moment but is it possible to combine with any other gift cards that I can get at discounted? Yes I realised I just missed out on the 30% off Adrenaline cards at Big W last week…

Appreciate any help I can get.