Hydralyte Sports Powder 900g tub at Chemist Warehouse for $36.49.
Can also pair with the Shopback Pay offer for an additional $5 off.
Amazon AU have price matched on the Lemon Lime flavour.
I recently started using Hydralyte Sports as I figured out I'm pretty salty, so needed something with a higher sodium content and it's working well. I did the sums and found this to be cheapest per serve with what I was looking for compared to anything else in tablet or sachet form. Worth noting Bulk Nutrients may be cheaper per serve, but you need to compare based on your needs (https://www.bulknutrients.com.au/).
Thanks, was waiting for this to go on sale.