Starting today BigW has 20% off all toys*.
Two of the best Transformers related offers I've seen are:
Power of the Primes deluxes are now $23, save $6
Power of the Primes voyagers are now $36, save $9

Interestingly the website shows both wave 1 and 2 voyagers, though I havent seen wave 2 in stores yet, but with any luck they will be there before the sale ends so keep an eye out for them.

Sale ends April 4th, *Excludes gaming, sporting, cycling, skating, scooters, price dropped lines and clearance items