You can use the word ‘spend’ only as a verb, meaning to - use money/time/energy for something:
He spent $200 to fix his car
We spend lot of useful time in watching cricket match.
He spends lot of energy playing tennis.
The word ‘use’ can be used as verb (to utilize, employ)as well as noun (meaning a purpose),
I am used to cold weather.
She uses her intelligence to solve difficult problems.
This computer is in use for more than a year