I got mine through customcruising
Very good if not the best wheel chock around

Easy Trailers in Bayswater has them $110.00, I heard Aldi had some a few weeks ago too

http://www.easytrailer.com.au/motorbike_chock.html

don't know why there postage has gone high I got mine when they first started selling online and postage was good

also supercheap $79 i think

Lot of Chinese cheap ones out there

I got two from Supercheap, they look identical to the ones you have pictured above.
I think they cost me around $75.00 per item.

They work a treat, Ive had my Superglide and a couple of Road Kings in them.

I have one of the supercheap ones on my bike lift that one of the pick above looks a bit better .tie down points maybe I have a early model
work good for the price you couldn't make one with time +steel and have had a few bikes on it now jap/dirt/Harleys