I don't know how this site get the information of double value offered for iphone. Say Iphone 4s worth $100.00 and walmart will double the values for $200. I bought the iphone 6 today and try to tell give me $200 for my iphone 4s very nice condition. Walmart could not find anywhere in there system to honor my request even I show this website to them. They call many store managers to question and even call Walmart corporate office and they don't know about the double vaule of your old phone. Again where do you get this information tomsguide.com ?