Normally in the low to mid $400's. Though this is a pre order as they don't have stock.
Dessiccant type dehumidifier. These are good in cool weather to dry out your room which can minimise condensation (and mould growth). I have the Ionmax612 and use it in a room about 4x7m which seems a good match. Much bigger a space I'd go for a bigger one. This brand is a Choice pick (not that I put much faith in Choice). Uses about 200-400 watts. On high is about as loud as a pedestal fan on medium/high. On low you can watch tv fine.
There are a few on this link
https://www.appliancesonline.com.au/filter/heating-and-cooli…
To help you pick between desiccant or compressor type:
https://www.andatechdistribution.com.au/blogs/news/desiccant…
My experience is I had a persistent cough that I just couldn't clear up over months (this was a year or so ago). I bought a humidifier thinking steam was the thing to do (like a Vicks steamer, which I also tried). Nope. My GP said his kids had the same issue and he spoke to a respiratory specialist who said in a heat pump heated home he should try a dehumidifier. It worked for him - and for me.
It also makes the room feel warmer (and can help dry out clothes on a rack).
Also a possible option would be the Breville All Climate (desiccant type) at $359 that mangalossi linked to in the comments. It does use more power and has fancier air filters - I always wonder about cost and future availability of filters for machines like this.
The Ionmax has a basic flat polyester (?) gauze type filter which looks washable. I don't think it'd ever need to be replaced.
I also recommend getting a simple indoor/outdoor temperature & humidity monitor so you know when to turn it on and when to air the house with fresh outside air (about $20-25).
Breville The All Climate Dehumidifier is also on sale, $10 cheaper than this and slightly better spec. I just bought one the other week and have no problems with it with reducing humidity in the room, especially in winter weather as the room can get below 10ºC.