That depends on how much prior service you want to buy, when you buy it, and how you pay for the purchase. The purchase can be very costly and may significantly increase over time. DCRB will calculate the cost based on actuarial assumptions and the rate of return earned by the Police & Fire Plan. Your cost will be an amount equal to the dollar increase in the present value of future benefits that results from crediting the prior service, as determined by an actuarial calculation.