It looks like JB Hi-Fi has some PlayStation 4 games for between $2 and $5. At least some of these (e.g. Shadow Tactics: Blades of the Shogun) I could not find cheaper. This does not appear to be store-specific. Here's a list:
- RAID: World War II ($2)
- PES 2015 - Pro Evolution Soccer ($2)
- My Time at Portia
- Strange Brigade
- Deus Ex: Mankind Divided
- BALAN WONDERWORLD (PS5)
- BALAN WONDERWORLD (PS4)
- Warhammer: End Times – Vermintide
- Helldivers Super-Earth Ultimate Edition
- NBA 2K18
- Mark McMorris Infinite Air
- Worlds of Magic: Planar Conquest
- PES 2017 - Pro Evolution Soccer
- Mighty No. 9
- AO Tennis
- Battle Chasers: Nightwar
- Shadow Tactics: Blades of the Shogun
- Vikings - Wolves of Midgard Special Edition
- Blood Bowl 2
- AwesomeNauts Assemble!
- Teslagrad
- Rabbids Invasion: The Interactive TV Show
- Titan Quest
- Professional Farmer 2017
Fallout 76 Wastelanders (PS4) is also $10.