What he said above^^^ Remains what is left in the rent.
Now you have to read the fine print. Depending on the state, if she asks to get out of the lease early, she’ll have to pay a closing fee and get burned a lot. If she has a deal with dealer A, who still uses the same leasing firm, and wants to get out of 21 a little earlier, the dealer will most likely throw her the keys to 2024 and send her on her way. no fees attached. Just pay the difference in price inflation in the monthly rate.
Remember, she doesn’t own the car! She can’t sell you the car! This must be done through the dealer or rental company. You will pay sales tax on whatever the dealer/firm says is the market price for the car. You will have to pay the fees moan. Including title fees and closing fees. The car is used, so there is no 2.9% financing.
If she had a crystal ball and could see 3 years into the future from 2021, lease with an option to buy, she bought, sold to you…that would be the best deal good for all parties 4x. It would just be between your bank and theirs to get the car.
I honestly think this is one to stay away from. Put emotions and impulse buying to bed. If the car is returned to the dealer, yes, there is a chance you can buy it from the used car dealer. If you go to a rental return center, kiss it goodbye. It will be auctioned. If you walk into the dealership with her and let her know you want to buy that car, you just became the target, not her. That dealer can just sit back (hides his smile) and probably pay you paperwork fees to sell you a car that may not be theirs (but will probably find a way) to cashed in on a car that never had to be touched. .