Ok there is a trade in offer look:

Power Trade - Fable 2, Fallout 3, Gears of War 2

Trade any games towards the reservation or purchase of Fallout 3 (PS3, 360, PC), Gear of War 2 (360) or Fable 2 (360) and receive an extra 20% Trade-in Credit!


can you explain exactly what does this mean

if you trade in games at gamestop you can use the money or store credits to to buy an upcoming game.

any games you trade in towards the purchase of one of those games gamestop will give you an extra 20% of the trade in value of your traded in games

if you trade in 25 dollars worth of stuff they will give you an extra 5 towards the purchase of those games

the catch is all the trade in amount has to go towards those games listed

Another catch is that the trade in values at gamestop suck

It means, if you are trading in older games for store credit, AND you are applying that store credit toward one of the above mentioned games you will get the extra 20% applied.

For example:

I am going to trade in Super Mario Party XXIX (fictional game) for a store credit of $10.00. Gamestop will apply $10.00 of store credit to my Edge card.

If, however, I am putting money down to reserve a copy of Fallout 3 (from your question), they will apply $12.00 towards the purchase cost of the game. They have in essence given me an additional 20% on the value of my trade in.

Hope this helps.