Take time to research and review local listings as a basis for how much to charge. Consider utilities such as electricity, gas, water, sewer, oil and cable before deciding how much to charge. Different investors have different goals. The difference between the total monthly cost of utilities, taxes and mortgage and the amount you charge may not be enough depending on your goals. Set your spread in relation to your personal goals and analyze the investment against the established amount. As an investor looking to make an annual profit with no additional costs beyond the down payment, I use a rule that has a spread of at least $500 per month between income and total cost. As an investor, the goal is to have a larger spread to make more profits. The spread can aid in decision making when considering other options to pursue