When I was buying mine I asked them about returning the phone because the way I was doing this I may have to return it (long story, short version is I was buying it with the wifes phone (hers was elligible, mine wasn't, same family plan) and then going to switch the phone #'s/phones around at the AT&T store because they said I could do that but Apple couldn't) and she said I could return it if AT&T couldn't do what they needed to do. I asked about restocking and she said they aren't charging a restocking fee at this time. Now that was on a flat out return. If you want a different model such as white for black, when nothing was actually wrong, they may still charge a restocking fee. It's within their right, I believe. But YMMV, every store and every rep is different and you may have luck one day doing a swap with no restocking and the next day at the same store they may not let you.
Just don't do as the other person suggested and lie and say there is something wrong. If you're doing that just to get out of a restocking fee that's considered fraud.
FYI, I like my white. Doesn't seem to scratch up nearly as much as the old iPods did. Seems like it surely has the potential to scratch more than the old iPhone though.
