For my adult dragons: Washed Playsand from Bunnings...
For my hatchling dragons: Astro-Turf (four sections in their enclosure, much easier to spot-clean and replace with a fresh-piece)
For my pythons: Astro-Turf (12 sections in the Bredli enclosure, 24 sections in the MD enclosure - MD enclosure is twice the size of the Bredli enclosure)
For my G. variegata: Red Desert Sand (holds heat in that side well - Heat-Mat used under one third)
For my U. milii: Red Desert Sand (looks good!)
For my N. levis levis: Red Desert Sand (tends to hold its tunnel shape longer than anything else I've found, AND it looks good with red geckos!)
For my daughter's Stimson: Red Desert Sand (because I stock it in my Reptile Room, and she gets it cheaper!)
I use Astro-Turf for its easy cleaning (just remove excess waste material first, scrubbing brush under hot running water, both sides, hang on the clothes line to dry, trim any frayed ends), longevity, cost-effectiveness and aesthetics. My number one beardie Leo had the same two pieces his whole life (just over eleven years). The only "downside" to this is, being in sections, occasionally, an escapee cricket that escapes the eagle eyes of the hatchlings gets in underneath. Mind you, when it come out at night to munch on the dragons' salad, there's usually one little vegemite awake to pounce!
The Red Desert Sand is great for geckos that dig burrows, as it tends to hold longer than other sands I've found (if anyone has any other ideas for levis, would love to know about it!), is really easy to spot-clean and is 'reasonably' priced. (I have suppliers for the Reptile Room, very handy!)
The Washed Playsand from Bunnings - well, the adult dragons' enclosures are fairly large, so I do use a "bit"... Cheap, easy to spot-clean, good for when the dragons dig. Only downside is it's packed damp, which is one reason why I don't use it in my snakes' enclosures, so when I've put it in the enclosure, I leave the lid (top-opening) open a little to help it all dry, and reduce the humidity in the enclosure.
Hope this helps! Great idea for a thread, by the way - and interestingly timed... SnakeBytesTV's latest edition is the top 10 substrates...!
Best,
Carolyn