In this example, that would require the “big query” to have billing baked into its actual query runtime, which isn’t impossible, just not how one would design a query planner per se. Usually such services emit metrics of usage units, then the billing calculation happens in a completely different system taking into account discounts, promotions, contracts, regional and currency differences, etc.

Suddenly a database, a storage service or a computer service needs to be aware of the billing situations and make behavioral decisions based on the billing status. Again, not impossible, but something that suddenly promotes billing from an async/non-crucial background service that can be paused, replayed, adjusted by account teams etc, into a crucial hot-path service.

The way you'd usually handle that AFAIK is to have the service ask the billing system for a "reservation" in its native units, likely with an attached TTL. Then, the service would translate those units to U.S. Dollars (or possibly Indian Rupees), taking your plan, discounts, vouchers, contracts, grandfathered pricing and all that into account. It would then "lock" the calculated amount of money, denying the reservation if total_spent + total_locked > spending_limit. After finishing the operation, the service would ask for actual billing and free the unused units.