The Microsoft Sculpt Touch Mouse at office works is $35.
https://www.officeworks.com.au/shop/officeworks/microsoft-sc…
After cashback 30% from Microsoft https://www.microsoft.com.au/cashback/
Final price would be $18.
Cheapest price on Ebay is about ~$37
For anyone concern about the Bluetooth disconnect randomly which make the review score of this mouse low, here is the fix. It cause by the power management problem.
http://www.thewindowsclub.com/bluetooth-mouse-disconnects
confusing indeed, no explanation of how much % you will get back if you pay for the product below/above their written RRP price.