While executive orders obviously affect how the executive branch spends money, it turns out no one is keeping track of exactly how much they cost.
The Office of Management and Budget has been legally required since last year to report the budgetary impact of each executive order, but specific information has not been forthcoming.
When an order goes into effect in a given fiscal year, it is funded by money re-appropriated from other parts of the executive budget. As USA Today explains:
Congress sets the budget, and the president can’t spend any money that Congress hasn’t already authorized. So at best, the president can only move around resources within existing line-items approved by Congress. …So the 1% raise Obama enacted by executive order…will come out of every agency’s existing budget.
But in subsequent years, agencies can request additional funding from Congress to fulfill executive order requirements, and that very real long-term cost is still unknown.