It has a lot of factors. Including the condition of the 360, and believe it or not if it has the box it came with and even instruction manual. It also depends on the GameStop. I'd say around $150 for an xbox 360.
I went to Gamestop today (03/17/2011) and they will only give you $40 in cash for your Xbox 360 and $65 in store credit.
My recommendations as a store employee:
$25 but if you have a pro membership you get an extra $25 but only this month
It depends on the condition, if its the elite it would be about $200, and if its a regular white one it would be about $120.
They sell for $75 on amazon and you would get less from Gamestop
20.00$
$20
About $26.95
They don't buy routers.
about as much as it cost
Not much
They would not buy a PS1 from you.
None!! If I sold my COD Black ops game at Gamestop, i would not give you any money!
nothing if you don't give them something