What are you going to do with the buggy? race? bash (play in the street). If you are going to race, I would get the b4.2 that comes out next week. If you need it to be an RTR, you could go with the B4.1 rtr, but I would get the racer and pickup cost effective electroncs
Here is my opinion of cost effective electronics.
Solar 770 servo
FlySky3b radio
gensace 50c 5000 mah battery
HW motor/esc combo
imax lipo charger (some are like ($30))
Most all of this can be purchased on hobbypartz.com.