Sometimes it just plane depends on the game and when you are trading. One day entertainmart gives more, then another GameStop. In most cases though with gamestop's reward program you will over time get more. There are also the perks that being a powerup rewards silver member get you on gamestop's side.
Personally, it is just good to call each store before leaving your house and ask.
if you trade and pay the difference at a pawn/trade store like entertainmart or gamestop
It depend if it is gamestop they will give 30 % of regular price
Around $20.
85%
up to 20$
No, but you get 10% of purchases and 10% extra trade-in credit if you have one.
i heard around 60 bucks
Yes, you have to still pay 75$.
45$
If your talking trade ins they are not that good at about $4.00
If you trade in a game for another game you normally have to pay them some.
As of Dec 2011, older model 15 trade in ,slim 25 Trade in.