Here is how a lease works.
New Car - Now worth $X.
Three year old car above - Projected to be worth $X - 30% or so, pick a number, say $20,000.
Take $20,000 and charge for a loan on that amount, X%.
Divide by 36 months - lease price. You pay for projected depreciation over 3 years. Beware the fine print, "normal wear and tear".
There are times they find some small paint chip and say "more than NW&T, you owe us another $500". Not everyone does this. They also use leasing to get you into a nicer car.