I find weights are generally priced at $3-4/kg. At $1.60/kg, this seems like a rather good deal (for one after a pair of 5/10kg dumbbells), even if not on "sale."
Note: The 20kg seems to include the iron bars and collars.
Update: I've just been to Big W, and noticed they've got the same for the exact same price (different brand, of course). Didn't buy it, in light of the comments here. Besides, as I said, it's not a "sale," so no rush.
for proper plates and up… not concrete or similar filled plastic shells.
Plastic spin locks I find also loosen real easy on anything except the lightest weights.
Price is decent though just don’t drop ‘em !