If a high refresh rate is more important to you than pixel count, the best 240Hz gaming monitor is remarkably cheap on Amazon Australia today. The Alienware 25 AW2521HF is AU$519 with free delivery for Prime members—normally it's AU$699.
Yeah, it's 1080p, but as above, you're buying this for its sky high refresh rate. We named it the best 240Hz offering in our list of the best gaming monitors, noting its "lightning-fast response time (1ms)" and handling of ghosting and artifacts. This model is 25 inches, and boasts AMD FreeSync Premium, along with G-Sync compatibility.
"The AW252HF has some impressive viewing angles regardless if you have it set in the middle of your desk for gaming or off to the side as a second monitor in portrait mode while you work," we go on. "Our only real complaints are the lack of HDR support, along with having not the best contrast."