General meaning:
* Expenditure: This is the most common noun for "expend," meaning the act of spending money or resources.
* Expense: This refers to the cost or amount of money spent on something.
Specific meanings:
* Outlay: This refers to the act of spending money, especially a large amount.
* Disbursement: This refers to the act of paying out money, especially from a fund.
* Consumption: This refers to the act of using up resources, including money, time, or energy.
The best noun to use will depend on the specific meaning you want to convey.