Here's a thing that should be part of character generation.
What does your character want?
- pay off a debt
- ransom/redeem someone
- purchase a costly treatment
- redeem ancestral land or possession
- support artistic career
- buy way into aristocracy
- pay tribute to warlord / bandits
- pay money to the druids for good crops next year
- pay to have loved one healed / resurrected
- pay for the mending of something broken
- pay off the weregild of the man I or a kinsman killed
- provide for family
- provide for the poor
- provide for my people
- give a certain amount of money as restitution to someone wronged
- live quietly and simply without care
- live the high life
- purchase the one thing I can't live without
- purchase generalship
- support my own outlaw band
- build keep to hold against chaos/law
- support my own army to overthrow ruler
- build a tower to carry on the research I really care about
- build the device that has haunted my dreams
- repay the being who opened the arcane to me
- create the potion that will cure my sorrow
- build a temple
- build and run an orphanage / leper house
- support holy army for the crusade
- support a missionary trip to dangerous lands
- purchase a building to serve as HQ of my own thieves guild
- pay off enough politicians to have the city in my pocket
- buy my way into the most OG thieves guild on the continent
- buy up all competitors in an industry
Season to taste.
When they get enough money to accomplish the goal, or accomplish it without having to get all the money, you've got two options: (1) retire to safety/despair after accomplishing goal, or (2) choose a new goal.
Your character can also choose to abandon the goal for a reason your character articulates or that is obvious from the fiction.
When you accomplish or abandon your goal, you have won D&D with that character.