Like Smarty suggested, go for one of those Numark "DJ in a box" packages because their perfect for a beginner and really good value too. There pretty much ideal for someone starting out, I started on one of these Numark packages then grew to love mixing and got a better setup after about a year.
dont buy cheap decks to start.... my mate brought the nurmark decks...and there good but hes looking to buyin technics....yeah technics are more expesive but in the long run there cheaper cos you wont ever need to buy another pair of decks...
my technic 1210s mk2s cost me £400 with a good numark mixer, 50 dance vinyl of ebay second hand...they are in mint condition!
have a look on ebay...£400 aint a lot of money cos you WILL buy technics if you get into mixing.