Seems to be the cheapest for the newer switch on Amazon AU according to 3camels. But not the cheapest ever, if you managed to grab an older version of the switch (I'm not too sure what the difference is between the old and the new). Tamagotchi Breeder lists the differences in a comment
Hope it helps someone!
(I copied the 'Delivery ($0 with Prime/ $39 Spend)' from another post - I've no idea if this is still true, and I'm struggling to find the current non prime shipping rates)
Thanks to nbn's comment:
Same price at JB HiFi so potentially you can get extra 10% off if you snapped the ultimate gift cards from WW previously.