Figures depend on provider and plan, but sometimes cheap (as per parent's 6c / kWh), but during the midday to 6pm range it may be up to 60c.
So, grid rates aren't subsidised, but having a storage medium means you can arbitrage power quite easily.
https://www.aemo.com.au/energy-systems/electricity/national-...
You can also view the breakdown of where the grid is sourcing energy from (i.e. what portion of the grid is supplied from solar pv etc at any given time).
I know that some big industrial users (large factories etc) can optimize/spin up production lines etc based on the spot price. Although I'm not sure if they use the same public AEMO data there might be a dedicated api or similar involved.