[PC] Anno 1800: Standard Edition US$19.80 (~A$27.18), Complete Edition US$49.99 (~A68.63) and Others (20-50% off) @ Uplay

Cheapest historical price for the Standard Edition according to isthereanydeal, and approx. equivalent cheapest price for the Complete Edition as well.

Other discounts include:

Season Pass 1: 50% off, US$12.49 (~AU $17.14)
Season Pass 2: 20% off, US$19.99 (~AU $27.43)

I purchased the standard edition last week for ~$33 bucks and am enjoying it a lot. I have friends who appreciate the content of the expansions but for now the base content has proved plenty of content for me, although I might pick up the Season Pass 1 as part of this sale.