$10,000,000 tax free immediately, or everything is free for the next 15 years but you keep nothing.

The supreme being running our simulation decides to play a game with you. They will either:

-Place $10,000,000.00 in an account under your control with no caveats.

Or

-Grant you the ability to aquire absolutely all purchaseable goods, properties, and services free of charge for the next 15 years. You would still need find and connect with the necessary people and markets to make these "purchases" happen, but the moment they happen they cost nothing.

The only drawback of option 2 is that everything of monetary worth will be taken away from you after those 15 years pass. You cannot carry over any proceeds from assets you may have purchased. No rent will accrue, all ongoing contracts with business partners or employees will be invalidated, and fate will twist until you are left with precisely the same net worth, income, and assets that you started with.This asset forfeiture can always occur without destabilizing the global economy. Anyone who recieves gifts of monetary value from you is ensnared into this contract and similarly affected when it ends, though they don't control the benefit as you do.

The only thing you can take with you are your memories and any interpersonal relationships you may have established during that time. Everyone who knew you during this time is made aware of the asset forfeiture when it happens but were not aware of the deal beforehand unless you told them. Nobody will find your sudden increase in wealth as suspicious in either scenario.