Keeping a car at the end of lease-term can cost you thousands more than it would have to simply have bought the car from the get-go.
Leasing does have its place, but it's not right for most people. If you're absolutely certain you don't want the car long-term, leasing keeps your monthly payments low. That's because the payments are based on the actual value the car loses during the time you're driving it. Instead of making payments then getting some money back when you trade the car in, as you do when you finance a purchase, with a lease you just don't pay that money out to begin with.