What iPhone should I get my 11 year old son?

David wasn't sure whether or not to get his son the iPhone 4 or 4S because the technology is old now. Leo says he should definitely consider those older models, though, because they are a lot less expensive. He should get a very good case for it. Leo thinks it's a great idea to get kids phones nowadays because it's good to be able to get a hold of them, and they should have them in case of an emergency also.