How much is my used laptop worth?

Jul 18, 2018
Hello, i want to sell my used laptop but not sure how much to sell it for.
IT is a Lenovo z50 15.6" 1920x1080 FHD with the following components:
-Intel i7- 4510u processor
-Gefore GT 840M graphics card
-12gb DDR3 ram
-1tb HDD

It is in a great condition, everything is working perfect including the battery, buttons, trackpad, screen, performance it hasn't fallen, just has a few small scratches on the top. Its fan has been cleaned and repasted, both carefullfy and properly, by me. It is 3 years old but it is hard to tell, and it also has windows 10 installed, but not licensed.
It would be great if you could help me with an estimate price i could sell it for,
Thank you.