Studio subwoofers are expensive in Australia :( These are currently about AUD$500-600 in the US and $750 to $1100 locally (if you can find them in stock). It does look like these dropped to $574.69 on Amazon AU for a week in Feb 2023 which would have been a bargain.
This sub pairs with the super popular and affordable JBL LSR305 MkII https://www.ebay.com.au/itm/390722482841?hash=item5af8dff299… but can be used with other monitors.
You might be able to get these cheaper from Amazon UK site if you pay in GBP ~$590.
Note the model name is LSR310s/230. I assume this means 230v model which I'm hopeful should work in Australia. You will also need an AU kettle plug / or adapter.
Here's to hoping that prime members get free shipping :p Unfortunately not…