The current value of Acer 5810TG-944G50MN

I have got such notebook in lucky draw, I have no idea the price to sell it in second hand market. Is there any C-Hing to suggest? I have checked it in Fortress is selling @ 7998
Cpu SU9400, 4G DDR3 ram, 500G HD, Ati 4330 GPU,15.6" mon. 2.4kg

What do C-hing think HK6400 is reasonable price?(20% off from original price)