http://forums.audioholics.com/forums/headphones-earphones/86206-dunu-i-3c-s-vs-hifiman-re-400-dunu-i-3c-s-doomed-loser.html
I am now sonsidering to choose one from the two earphones, both are about 100$,
As for your budget is 50$,I am not sure those can be your choice