Suppose that you have the option to lease a new car, which you can otherwise purchase for $$21,000.$ The lease terms: $$3000$ down and payments of $$317$ per month for $48$ months, at the beginning of each month. Upon termination, you can purchase the car for an additional payment of $$7000$ at lease expiration. If your financing rate is $9\mathrm{.}2\%$ APR, and you intend to finance the purchase of the car, how much do you gain $(+)$ or lose $(-)$ by buying the car instead of using the lease$-$purchase option?