Can I sell or trade in a leased car?

Often, yes. A dealer or buyer pays off the lease using the lessor's payoff quote, and if the car is worth more than the payoff, you keep the difference as equity. Some lessors restrict third-party buyouts, allowing only their own brand's dealers to buy the car, so check the policy first. On OffLot, the Trade-in and Sell my car pages estimate equity by subtracting your payoff from the estimated value.