Noticed this while doing a bit of shopping at my local Woolworths (Ashfield, NSW). Had been keeping an eye on it and never on sale whenever I look (as jv pointed out I didn't look hard enough). Now it's over 50% off but only applies to the limited edition Berry smell. Doesn't smell that fabulous but can later change it to the other refill smells.
(http://www2.woolworthsonline.com.au/#url=/Shop/SearchProduct…)
Got myself one and worked on checkout. For those who are wondering, the spray machine is in the pebble colour look.
You haven't been looking hard enough then…
https://www.ozbargain.com.au/search/node/Glade+Sense