Request for advice: How much is 2012 Macbook pro worth?

Hello!

I'm looking to sell my 2012 macbook pro but I'm not really sure what a good base price would be. It's 15 inches, has 8 gb 1600 MHz memory, and 500 gb of storage! It still runs very well and the only scratches it has are on the bottom! I'm trying to raise some money for my books next semester but don't know much about computers much less how much money I can hope to gain so any insight would be greatly appreciated!