A decent price, not far off the $17 Boxing Day Price and the cheapest we've seen since then.
(1) This is price matching The Gamesmen. You could pick it up there for the same price in Penshurst NSW. Also dropped to $25 at EB Games eBay, Free Delivery with eBay Plus.
(2) No Man's Sky 'Beyond' is an update to the original game, not a new game. You could buy the original game then update it, however it's not any cheaper currently.
(3) Part of Days of Play deals.
New Amazon users may want to combine it with other games to get $10 off via the app ($39 Spend). See here for other Amazon PS4 game deals or the Amazon Store for everything. Spiderman is $19 exactly ($20 + $19 = $39) for those wanting to hit $39 for app or free shipping purposes.
5/6: Available again for $20.