Systems and methods for tracking and billing expenses throughout a transaction, such as the sale or management of a real estate property. In one embodiment, a budget is created that details expected incomes on the property and costs associated with the sale or management of the property. The budget may be developed in accordance with specifications, such as line item maxima or total budget maxima, developed by the owner of the property. After a vendor has delivered goods or services described in the budget, the vendor creates an electronic invoice. Payment is delivered to the vendor through an Automated Clearing House system.