This video, from the always-great LinusTechTips, is perfect if you're upgrading or building a gaming PC before the end of the year. The beginning is a straightforward rundown of which video card you should buy, and after the TLDR section is over, the nitty gritty of price-to-performance comes in.
The first chunk of the video is the TLDR section, where Linus runs through the best video card option for each price point. Of course, he's referring to US prices, so Australians will find the cards a bit more expensive. For example, if you're looking for something at a cheaper price point, you can't go wrong with AMD's Radeon RX 460. Bump that up, and the NVIDIA GeForce GTX 1060 is an all around solid performer at a good price, and if you have a little more money for a little more performance, the Radeon RX 480 is worth considering. Higher than that and you get into the "enthusiast" realm, where he recommends the NVIDIA GeForce GTX 1070.
You should absolutely check out the video for specific manufacturers and brands he recommends for each of these -- some of which are better than others (for example, he recommends EVGA thanks to its customer support and warranty options for some of the cards), and then if you're interested in the nitty gritty of how he compared the performance of each of these cards to its price, stick around until the end of the video.
When he did that comparison, he used the spreadsheet linked below, which you can download from MEGA and toss into a Google Sheet to play with yourself. All in all, you can input the prices for various cards in your area, and look at the benchmarking results across all of them to choose which one is best for you.