Id wait until you can afford a half decent one. Unless as said above you have loads of the bits anyway and know someone in the trade to paint it for you.

Youll be looking at about £3k for the engine and a few grand for the re-spray so thats about £10k before you even start with the little bits and pieces.

Then even when it is all done, it will still have a history and most people will spot that its had panals.