One of my all time favourite games. Be aware though that Year 4 is just about to begin, and the Complete edition contains content up til Year 3 only. In addition, VIP membership does expire for this purchase 31/01/19. That said, it's still a fantastic amount of content to play with if you're just starting out or don't want to grind to get the rest of the operators.
All editions of RS6: Siege are available for 70% off (Standard/Advanced/Gold/Complete). Personally I think the complete edition is the best as you get 2 years worth of operators for another $20 over the Advanced edition. Ubisoft link has a fantastic comparison of the editions.
No VPN required since they're all Aussie stores. It can be found $12 cheaper on PC from [this post] (https://www.ozbargain.com.au/node/427054) however requires a bit of work with a VPN which might not be for everyone.
Xbox
[Microsoft Store] (https://www.xbox.com/en-AU/games/rainbow-six-siege)
70% for those with Xbox Live Gold, 60% off for those without.
PC
[Ubisoft] (https://store.ubi.com/anz/game?dwvar_5a74872229e123bf13fea7e…)
[Steam] (https://store.steampowered.com/app/359550/Tom_Clancys_Rainbo…)
As far as I can see there's no love for PS4 players :(
As it says in top banner might as well redeem with 20% off with 100 club units which brings it down further to $43