I agree with KDF5...KFT5X...err...the person above me.
Go for 800 N kit as far as you can afford and save up for the rest later if you can't afford all at once. Personally I would get, in the following order, jacket, plastron, breeches.
Remember, 800 N does not only offer better safety, but also a 2nd hand value should you want to quit the sport. Happy shopping!
