Seems cheap for the random around home DIY opportunity. They use a li-ion battery, and have battery indicators. There is also a $29 li-ion 12v combination set including a drill and impact driver at masters too.
With credits to PLA74, here is the product featured on the 909 site:
http://www.909.com/index.php?page=shop.product_details&flypa…
Dont forget the 15% off
https://www.ozbargain.com.au/node/139922