As a guide you will need:
Car kit
1 pack of Lipo cells
Charger to suit above lipos
brushless motor
ESC to suit above motor
Servo
Transmitter/receiver
You can cover most of these with the B4-RTR (ready to run), which just needs cells and charger. This is good, but comes with a brushed motor and steer wheel transmitter - so could be better.
But you would get a better car if you carefully choose a kit and parts. BUT(#2) this would work out the most expensive short term - least expensive long term as you won't need to upgrade so soon.
Heres my recommendation:
Rc10-B4 stealth kit
Trakpower 3600mah cells
Losi AB9603 charger
Losi Xceleron Motor+ESC combo (with 8.5 / 10.5 motor)
Savox SC1258 Servo
Spektrum DX3S transmitter/receiver set. (steerwheel)
or Futaba 3GR transmitter/receiver set (stick)
A big tip from me, is make a list of the components you need and choose carefully which make/brand you will go for. Ask here or at the clubs, but don't rush into anything your not sure about, the sport/hobby is a LOT of fun but only if you make good decisions early on.
bad decisions leads to dissapointment and expense.
Chris