Ghostwire: Tokyo

I recommend you complete the main story before going for this, naturally you'll spend money over the course of the game.

Once the story is done go for to spend a bit more cash

Finally to boost the remaining money head to these two shrines:

• Hitani Shrine

• Toyoi Shrine

Both of these shrines have Offering boxes, simply go between the two donating 5,000 each time.
It takes a while of going between the two but eventually the achievemnet will pop.

I recommend you complete the main story before going for this, naturally you'll spend money over the course of the game.

Once the story is done go for to spend a bit more cash

Finally to boost the remaining money head to these two shrines:

• Hitani Shrine

• Toyoi Shrine

Both of these shrines have Offering boxes, simply go between the two donating 5,000 each time.
It takes a while of going between the two but eventually the achievemnet will pop.

Found an glitch for this on accident when I needed to reload a save for a Yokai hunt. From what I'm seeing you should normally get this through your save, but the game keeps this tracked across saves. So you can easily get this achievement by reloading saves and buying the same item.

So for example if you save, then buy "KK's Investigation Notes 02" for 100,000 meika from the Musical Nekomata(you can buy anything from anyone), then reload the save and buy the notes again, for some reason the game keeps adding those together.

So realistically you can get this as early as you want, but the quickest ways would either be to have 56k buy talismans and reload, or 100k buy the notes and reload.