"Fuel budget", "mass budget", "payload budget", even "delta-v budget" are common terms in spaceflight and refer to how much of a valuable thing a spacecraft can carry given some pesky laws of physics [1], nothing to do with money (except insofar as more money would let you build a bigger spacecraft…)

[1] https://www.kallmorris.com/columns/tyranny-of-the-rocket-equ...