The main problem is that te price says nothing about the qualitiy of the headphones.
First of all: "big" headphones are usually better than small ones, the bigger membran allows them to have a range that little plugs can't reach.
Most of the headphones you can buy are just bad, no matter if it's a 7? ($or whatever) plug or a hundred and more for big ones. They usually have too much treble or way to much bass, because that's what people think would sounds good. Too many treble sound thin too much bass muds the sound (and your ears).
You should check the frequences, here an example of a Senheiser HD800. A linear line would be the optimum for a box, with headphones that's not quite the case, but close.
If you actually get a good pair, then they are definitely worth the investion.
V-moda used to make qualitiy in ear headphones. But they got way expensive and tend to break quick (cable issue)