Hi all. I'm totally new to this stuff, but I'm purchasing a drum machine to practice with that has one stereo 1/4" output which doubles as a headphone jack. I want a small mixer (cheap but effective) that will mix that with my MP3 player (obviously stereo). The mixer needs to have a headphone jack which I will use most of the time, but I have an amp that I would like to have the option of outputting to that would mix the mp3 and the drum machine. Can anyone give me examples of little mixers that will help me do all of the above? Thanks in advance!!