Well, Cheap one you can either have those that doesnt sound as nice. The quality is just wrong. While nice one have good bass and good treble. Their sound are perfect.

Currently i am using my old earphone from my Ipod. Coz my ipod is using the inear earphone.

I like in-ear earphone. Very nice

Well.. Bass is the lower tone. The music you hear at clubs and all those cars that sound as if some one is blowin up the city. Those are bass.
Treble in the other hand is the other side of bass so to speak. high tones, sharp sound. More widely used in singing ( i think, not so sure)