You are tasked with evaluating the purchase of a vending machine for the snack room. The total initial investment (purchase, modification and investment in net operating working capital) will be $6,000. The machine will result in operating cash flow of $2,400 per year for three years. When the machine is sold at time period three the net sale price will be $1800. The firm will also recover the investment in net working capital of $441. What is the net present value of the investment if the required return is 12%