A need is something that is essential for living – like food, water, oxygen. Without it, after sometime we are likely to die.
A want is something that makes life easy, fun, beautiful.
Even clothes might be considered wants if we consider that ages ago some people roamed nude, and some tribes even do today.
We use a washing machine to wash clothes today, before we used to wash clothes by hand. A washing machine is not a need , but for me has become a need, though not like food, water or oxygen. I can live without it but it makes my life difficult. I prefer having it.
Such things can be extrapolated to almost anything in the world – blender, television, internet, mobile phones, iPad, iPhone. None of these are needs but life often becomes difficult for certain people depending on what they are used to.
Yes, I do agree that marketing and advertising creates needs out of wants and luxuries, but that would have been said of the washing machine when it was first invented, or the computer, laptop, mobile, etc
So although we might think that the iPhone and the iPad are wants or luxuries and not needs, a time will come when we might think of them as needs, not like food, oxygen or water but like the washing machine.
A lot of these depends on what one earns and what one haves relative to others. Almost all people in India in urban cities have a mobile, so a mobile becomes a need. It is not costly and almost everyone can afford to buy some form of mobile.
A iPhone or iPad or tablet or touch-phone is costlier, not everybody have it and not everybody can afford it. Hence that is like a want today.
Wants and luxuries can become needs for the person or whole population/society/civilisation over time. The concepts of frugality, minimalism need to take care of this fact and we need to be aware of this as we lead our lives and make use of material things for wealth according to our life-situation.