The Tommee Tippee nappy disposal system normally costs $40 but is half price at Big W this week.
The expense of this system is really the refills, not the actual bin.
We found using the system for poo nappies and not using it for wee nappies helped reduce costs.
This item doesnt appear to be on the Big W web site - not sure why.
Mod Note: Updated URL
you can buy cheap rolls on ebay to refill the expensive cartridges ;)