The same thing anything is worth: Whatever someone pays for it.
Assuming you're an adult, you should have known that.
Whether KBB, Edmunds, Nada, or anything else gives it a value, nothing says you can sell it at that value.
So, whatever someone is willing to give you cash in hand.....that's what it's worth. Might be $1000, might be $10.
List it on Craigslist, OBO, and see what offers you get.