what does cargurus.com charge to sell my car

I purchased a car out of State and am waiting for the title to come through to purchase the tag and paid the tax and registration.  In the meantime I have found a different car locally that I would like to have.  I understand I have to register the car locally and buy the tag locally and cannot just have the new buyer take over the sale.  What does it cost to us Cargurus to sell my car after I purchased the tag and pay the tax locally.