Help with trading in psp 1000 and games?

I'm going to buy a new psp 3000 and I have $175 saved up, but i need $25 more dollars to buy it. So i want to know these trade in values in gamestop:

PSP 1000

Sonic Rivals (PSP)

Thrillville: Off The Rails (PSP)

Mario and Luigi: Bowser's Inside Story (DS)



PLEASE HELP!!!Help with trading in psp 1000 and games?
Call your local GameStop, silly. If they're too busy, call a different one. Most city GameStops are open til 9:00 on Sundays, so try some cities like Cincinnati, Austin, St. Lewis, Indianapolis, Lexington, or Detroit. Call around until you get someone who will look it up for you. When they answer, say something like "Hello, I've got 4 things I need the trade in value on, do you have time to help me?" If they say No, call the next one on the list.