Just grabbed a Xiaomi Mi Anti-Formaldehyde Filter at Kogan for $39.00 shipped free using my free trial of Shipster.
Seems like a really good price for a genuine filter if you can use the free shipping option with Shipster and still a good price if you have to pay the $9.00 shipping.
I have one for my hayfever and it's great and as a bonus, we moved in to a new build and the yard is a dust bowl and the dust has been absolute minimal in my living room where I have the unit placed.
Have extended the use of my 'basic' one that came with the unit, by giving it a vacuum occasionally, but I'll need a new filter soon and $39.00 delivered for a genuine filter looks good to me!
EDIT - I forgot to say that they have the 'purple' Anti Bacterial version for the same price. Do check out the specs of each colour to see what suits you best.
From the web page….
The Xiaomi Mi Anti-formaldehyde Filter for Air Purifier features a 3-layer filter design that effectively removes pollutants from the air.
- Unique bucket-shaped filter
- 3-layer filter design
- Removes formaldehyde, PM2.5 and other pollutants from air
- Filters out 99.99% of organic matter
- Easy to install
The Xiaomi Mi Anti-formaldehyde Filter for Air Purifier consists of 3-layers: elementary filter cloth, efficient filter material and activated carbon filter. The first layer filters out hair, paper pieces, etc, while the second layer can effectively remove dust and pollen from air. The activated carbon filter is used to absorb other harmful substances from the air and gives you fresh and clean air to breathe in.
I have to say * (profanity)* 99 bucks from dyson!