The best way to save money, is to optimise your energy consumption.
On average a 14.3 kWh battery should be able to save you roughly $5-$6 a day, depending on how you charge and discharge it. That's essentially just over $2,000 a year of savings on your energy bills.
We've put together a basic return on investment calculator, which will help you understand when you're likely to get your money back from your system. It doesn't take into account all of the nuances of your consumption, but it gives a rough estimate of what you could expect to save on a daily and annual basis.