Chasm

Spend a total of 5,000 gold across any of the shops opened up by Dom, Narina, Ash, Ethel, or Duncan. You need to rescue them first and, in some cases, complete their quest before they will sell you anything. Money spent is carried across all playthroughs, so this should come naturally. Money drops from monsters, lanterns, breakables, etc. Also, you can sell things you don’t need to the appropriate villager.

You can track your progress from the main menu by selecting “Extras” and then “My Stats”.

If you want to, you can follow this guide by Neme: Big Spender Trophy Made Easy.