An expense is something that a person spends money on. Bills, rents, mortgages, and purchases are examples of expenses. The word "expense" is different from the word "expensive." Use the word "expense" as a noun:
Vanessa’s monthly expenses are too high. She should cut back on spending.
There are many extra expenses that go along with owning a car.
After deducting their expenses, the owners of the company discovered they made a profit.
Owning a house is a huge expense.
My daily expenses are very low.
What are your living expenses like?
A car is an expense that I can do without. (do without = don’t need or don’t want)