John and Sally Claussen are considering the purchase of a hardware store from John Duggan. The Claussens anticipate that the store will generate cash flows of $70,000 per year for 20 years. At the end of 20 years, they intend to sell the store for an estimated $400,000. The Claussens will finance the investment with a variable rate mortgage. Interest rates will increase twice during the 20-year life of the mortgage. Accordingly, the Claussens' desired rate of return on this investment varies as follows:

• Years 1-5 = 8%
• Years 6-10 = 10%
• Years 11-20 = 12%

What is the maximum amount the Claussens should pay John Duggan for the hardware store?