Okay so I need help in deciding against the iphone 4 and iphone 3gs both 16 gig. My friend is selling her iphone 3gs for 200, its in really good condition and its unlocked and can tether. It would only be about 25 extra bucks a month for that. On the other hand I have an upgrade up in August and the Iphone 4g is 200, but its an extra 45 dollars a month. I do not make a lot of money and id be paying 85 a month for the iphone 4. With the 3gs id be paying 60, which is more reasonable for me to be paying. Should I go for the 3gs or iphone 4. What is the better investment!?