Here's a fact of life: No one wants something for FREE!
If she had put a value of $200 on the piano, more or less, someone would have bought it real quick.
So if you want to get rid of something quickly, the worst way is to say it's free because it means to the other party that it is of no value to you so why should that take something that is of no value? If there was a small price on it, even ridiculously small, it means that there is value that is exchanged. Go figure.