Reply to I need help please!

Hello. At the moment i have a hercules dj rmx and an akai mpd 26.

I am bored of the rmx and am so limited to it, wanting to move to traktor from vdj as well.

Anyway i have a ~$300 budget, and here is the thing. I want something very small, which I can bring to school to practice with in my lunch. I was believeing about the faderfox dj3, which has no soundcard and is expensive (270$) but is perfect, the behringer cmd mm1 (170$) which has no soundcard, or the xone k2 (350$) which has no crossfader, but has a soundcard. Does anyone happen to know any other controllers like these, i dont need jogwheels. to be honest i do not kno alot about djing, i just fade songs in and out, and would like to learn traktor as best as i can. I do not get why u need jogwheels besides scratching and forwarding and rewinding. Is there a purpose im not missing? Also if i do not have jogwheels how do i go back to a part of the song? I do not know what cues and cups are for, and i believe i am djing completely wrong. Traktor also has no stop button; a button which returns u to the beginning of the song, but my hercules does. Also i do not know why some people dj without headphones and some with, i find it easier to use them but what about people that use launchpads and do like one hour mixes? how do they know? Should i buy an audio card or what? There is so much i dont understand and i know this is alot to answer but please help me.