How much is my mac worth??

How much is my mac worth/ how much would it be for me to resell it to a 3rd party, here are the specs: Late 2009 unibody macbook pro 2.53Ghzl intel core 2 duo processor (logic board replaced march 2012) 8 gb DDr3 1333MHZ ram corsair replaced november 2011 Seagate Momentus XT 500GB 2.5 Inch solid state hybrid drive speakers replaced in march 2012 batter and power adapter replaced in january 2012
(i know this isnt the right forum but i could not figure out how to create a new post because i just joined and my account hasnt been approved yet)

also if anyone is interested in buying it i am in the market to sell