145 USD, no case, no power supply, it's available on amazon and aliexpress too but more expensive (around 180 - 200)
https://world.taobao.com/item/562199114522.htm
It's still too expensive, except you're interested in this product for the DIY project, like creating:
-low profile PCI-E card dock
-1 slot PCI-E card dock
I think it's possible to break the limit of SFF graphics card dock but with internal power supply, if Aorus Gaming Box or Zotac AMP Box Mini isn't small enough for you but still want non-soldered/non-MXM dGPU.
EDIT: Just rough calculation, with 150W AC-DC adapter (71x171x40mm), LP 2 slots graphics card, the case volume just ~1.6 litres, not forgetting the room for wiring and the TB3 board
Come on China, I expect you to release an affordable Thunderbolt 3 GPU dock, like 100 USD with power supply and case.
6.5 - 35 USD, PCI-E riser with mounting, like the current trend in some ATX cases
https://world.taobao.com/item/548239737967.htm