How much would game stop give me for these games?

Remember these are 360 games and i want a reaI money value. I am giving games to game stop to buy homefront. Please give the truth how much would they give me for these Fallout 3 add on disk the Pitt and op ancherage, Project gotham racing 3, fallout 3 add on disk broke steel and point lookout, war hammer battle march, burnout revenge, pirates of Caribbean at worlds end, halo 3 broken, fallout 3 broken, and Halo ODST