In today's tight market, used car prices are way up - Carvana offered me what I had paid for my 2015 three years ago - check for similarly equipped & year cars on Carvana and Cargurus and compare with what BMW is offering as a buy out. If still high, when you turn it in, see if the Dealer is going to re-sell it - BMW will be giving it to them at a discount that they just write off. You may be able to work a deal, and as a low mileage lease return in good condition, the Dealer will be selling it as a CPO, which means BMW will add another year of warranty to the car.