Hello mate,
Probably be best to see what clubs run nearest to you no point in buying something on a budget then having to do £20-£30 in fuel every week to go and race it.
I have just invested in a set up for 1/10th 2wd electric B4, (not had a chance to race yet though)everything was bought secondhand bit by bit. It would have been under £250 if I hadn't have blown an esc.
If you prefer to buy new I belive you can buy an annsman mad monkey kit fairly cheaply, then go for a hobbyking sensored esc and motor I think you will get this lot all in for around the 250 mark maybe less.
All you need to add to that is batterys and transmitter/reciever combo.
Good luck and enjoy shopping