Somebody told me that you take old used/old cellphones for parts or recycling kinda like that machine that was inside tha mall...is this tru?

Its true but i think its only for some gamestops because the one in my area doesnt seem to do that. But selling parts to gamestop im sure you wont get as much as you think. You should google if a gamestop does exchange parts or ask directly if youre still willing to trade parts.

You should call the specific store to ask, each one is different