expense

expense /ɪkˈspɛns/ noun
plural expenses
expense
/ɪkˈspɛns/
noun
plural expenses
Britannica Dictionary definition of EXPENSE
1 
[noncount] : the amount of money that is needed to pay for or buy something
— often used after at
— see also at someone's expense (below)
◊ If you spare no expense, you spend as much money as you need to in order to make something as good as possible.
2 
[count] : an amount of money that must be spent especially regularly to pay for something
— usually plural
3 
[count] : something on which money is spent

at someone's expense

1 
: paid for by someone
2 
◊ If someone makes a joke about you or laughs at you, the joke or laughter is said to be at your expense.

at the expense of

: in a way that harms (something or someone)

go to (the) expense

: to spend money on something