No, you don't have to accept her offer, it is your choice, but you identified the choice you face: take $3,000 in hand, or spend $7,000 to move something worth $15,000. It is purely voluntary what you choose to do, just like it is voluntary on the part of the landlord to offer money (and how much to offer.) If you can afford to pay $7k, it sounds like you'd be better off moving out--you'd essentally net $8k ahead. But if you can't pay to move it, you should take the money.