Total powersystem cost:
Motor $33 (Turnigy SK Aerodrive XP 35-48-1100)
ESC $44 (Turnigy Plush 60Amp)
Battery $33 (Rhino 4S 20C 2350)
GP med Electrify mount $16
Total cost $126

You will need to get a balancing Li-poly charger capable of charging 4S packs if you don't have one. There are many on the market. HC has several with built in balancers. I use a Triton 2 with equinox balancer and a Hextronic 8080 from HC. Both work great. The 8080 was $27 from Hobby city.

Take care,