Xbox 360, PSP, and DS used prices?

Ok so i'm trying to sell All my videogames to buy a nikon d3100 slr. I wish i never spent all my money on these games i have and now i have some questions.

my xbox 360 was bought about 2 years ago, the one with 20gb hard drive. It has had the red ring of death once and it was fixed. It has nearly no scratches but the disc tray cover is sort of rusty looking i guess and a few tiny brown spots on the console top. I want to know how much i should sell the console for. It would be this= Xbox 360 with 20gb HD, 1 controller, power cord, tv input cords, oh and the console has an HDMI port, so how much would this go for used?

my psp is a slim psp 2000, it was bought about a year and a half ago. Its silver and has the power supply. It has nearly no scratches except for one small one on the back. How much would this go for used?

my DS is the special edition pokemon one with palkia and dialga imprinted on the front. It was bought about a year ago and has tiny scratches only seen with light directly on it. It comes with the charger, a special edition pokemon case it came with, a poster, a dvd, and 2 extra stylus'. How much would this go for used?

thanks to all who can help me i really need it!

Hmm,

@ a store, like gamestop,
360: 80$
psp: 30$
ds:40$

these are just educated guesses, you could call the store and they would tell you