HOw much would i get if i sold my ps2 phat vers. to gamestop or gamecrazy?

i have a wii and xbox 360 so basicly my ps2 is just collecting dusts in my closet for years now.
how much would i get if i sell it with no controllers? just cords?
i saw on gamestop.com they sell the used ones for 69 bucks so iguess theyll buy mines ofr like 15-20 bucks? lol idk but how bout gamecrazy?
please help thankz