Put away the fancy and overcomplicated professional DJ equipment, there is a simpler option out there. The Micro Mixer DJ-4 is as bare minimum of a DJ setup one can get. It has two plugs that can connect to any MP3 player (or any other audio source) and two volume knobs that allow for seamless track switching and minimal mixing.

The pocket-sized mixer may not be the most advanced DJ utility, but that is the point. If you really want advanced pocket mixing, there are other options, but at $133, the Micro Mixer DJ-4 is great for the amateur party host or beginner jockey.

Micro Mixer DJ-4, via Gadgettastic