These are normally $12 at BigW, but Kmart Sunnybank Plaza had reduced them to $4 (on 31/10/16) and now they have been reduced further to $2.50.
Edit: This is available at all Kmart stores. (Confirmed by doweyy)
Bring instant light to any room with the Mirabella Dimmable Infrared Heat Lamp 275W. This large clear lamp globe is dimmable to create customised lighting and offers a lifespan of up to one year.
I work at Toowong and can confirm that this price would be universal, ticketed items are universal prices. The only differences between stores is when there are yellow/orange/blue stickers on the products themselves.