Infinite Happiness Paradox: You Can Choose Any Price But You Won't

Choose a price to purchase the lamp that will grant you anything you want. But you must at some point in your life sell the lamp for less than you purchased it for. We can prove that there is no amount of money that you should pay for the lamp; we can also show that there are infinitely many amounts you can pay for the lamp that will leave you better off. Which is it? Which is the better argument and why?