Yesterday I pulled the trigger and purchased the iPhone 4 (which I love BTW). Saw in the local paper that Target buys old iPhones! So with the money I got from Target (in the form of a gift card), my iPhone only cost me $95 (plus sales tax and that $18 upgrade fee).
It was in pretty good shape. It always was in a case and I used screen protectors. There were minor scratches on it. The guy basically went through the questions at that nextworth web site. The questions were: