The closest I came to that size electric was a T-Rex 600 which is a 50 size heli.
It required 6s lipo just to run the motor and a seperate 2s lipo for the rest of the electronics.
6s lipos are $200 each.
I used an Astro Flight 109 charger $139 will charge up to 9s lipo. Along with the charger I also used an Astro Flight Blinky balancer $25. and a power supply $50.
The setup required a 75A ESC and a seperate BEC.
Add in the motor, servos, receiver ect... you can plan on real close to $1,000 plus the cost of the airframe itself. (I calculated that at buying 2 6s lipos so you can get more than one flight in)