operating budget vs operating cost

operating budget and operating cost both are nouns.

Word	Noun	Adjective	Verb	Adverb
operating budget	Yes	No	No	No
operating cost	Yes	No	No	No

operating budget (noun)	operating cost (noun)
a budget for current expenses as distinct from financial transactions or permanent improvements	the expense of maintaining property (e.g., paying property taxes and utilities and insurance); it does not include depreciation or the cost of financing or income taxes