@Tigerlilly2332 I apologize for the late reply. I didn't have time to respond to you when I originally saw your post, but I guess I just forgot to set it aside for later. Anyway, yes, you can get a very good laptop for Sims 4 for $900 AUD or a little less, depending on how good you want the computer to be.
These two laptops, both on sale for $900, are as good as you're going to see at that price (and considerably better than you'd normally find), and they'd both have no trouble running all Sims 4 content on ultra graphics settings. The processor is better in the first one than in the second, but that won't much of difference to Sims 4; the graphics card will be the limiting factor here. I'm listing them both in case one isn't in stock. They're otherwise the same laptop: their other hardware and chassis are the same, and you can expect equal performance out of their other components.
https://www.harveynorman.com.au/acer-nitro-5-15-6-inch-i5-11400h-8gb-512gb-ssd-rtx3050-4gb-gaming-laptop.html
https://www.harveynorman.com.au/acer-nitro-5-15-6-inch-i5-11300h-8gb-512gb-ssd-rtx3050-4gb-gaming-laptop.html
This is a slightly cheaper gaming laptop, also massively discounted at the moment. Its graphics card is slower than the one in the laptops above but still capable of ultra settings. All else being equal, I'd get the faster graphics card for an extra $50, but if you like this one better for other reasons, it's a perfectly legitimate option. It does only have half the storage of the ones above, but that's still enough to fit Sims 4 and all your user content.
https://www.jbhifi.com.au/products/dell-gaming-g15-15-6-full-hd-120hz-gaming-laptop-intel-i5-gtx-1650
Below this price point, you're looking at laptops with only integrated graphics. The ones below have the fastest iGPUs available, but they're still much slower than the dedicated cards above: the 1650 is more than twice as fast as the fastest integrated chip, and the 3050 is ~30% faster than that. So if your primary concern is performance, you'll definitely want one of the options above or something like it.
However, if you're looking for something more lightweight and portable, or something that doesn't look like a gaming laptop, and you're okay with high or medium-high graphics settings, there are other good options as well. This one has the fastest iGPU available in a laptop at the moment, as well as 500 GB of storage like the Acers:
https://www.officeworks.com.au/shop/officeworks/p/acer-15-6-aspire-5-notebook-core-i7-8-512gb-black-aca51572u4#specifications
The integrated graphics chip in these three is a little slower than the one above, but medium-high settings should still be doable. The first is $700; the others are $800 like the one above but are worth considering if you happen to like them for other reasons. Their performance should be roughly equivalent, since they have the same hardware, other than the extra storage in the third one; the only other meaningful difference is the 14" screen in the third.
https://www.harveynorman.com.au/hp-15-6-inch-i5-1155g7-8gb-256gb-ssd-laptop.html
https://www.harveynorman.com.au/asus-15-6-inch-i5-1135g7-8gb-256gb-ssd-laptop.html
https://www.harveynorman.com.au/acer-swift-3-14-inch-i5-1135g7-8gb-512gb-ssd-laptop-1.html
If you have more questions, or are looking for something a bit different, please feel free to ask.