well you need a set of cd or vinyl decks and a mixer. then an amp and speakers.

stick with something pioneer for ya cd decks - cdj's. get 100's if you're on a budget, 800's are club standand but get cdj1000's if you can. don't bother with the cheap shitty other stuff.

if you're doing vinyl, get technics 1210's.

as for ya mixer, well you're only messin around so you don't need to break the bank but it's gotta be 1/2 good. i just went on decks.co.uk and saw this:

Behringer DJX750 Mixer

for the price, you really cant go wrong. never used it, but behinger stuff is usually 1/2 decent for low prices.