With a heli, just buy a 55 gallon drum LoL.

Ball Link Plyers
Wire Ties
Pitch Gauge Or just use you buddies if ones available
Hex Starter Adapter -I personally use the Ergo one-Blots on starter-Great for Less $$
Small Good Quality Screw drivers -I use Snap On Small Phillips locks in better than anything I've used before
Field Box -With FB battery-Panel that shows output to glow plug & charges Glow Starters-
Starter r-Good Quality One
High Point Balancer
Blade Balancer
Locktite-Red-Blue Types
Dremel-Optional
Metric Allen Heads
Plug Tool
Needle Nose Plyers
I use Kalt Filter on my heli's & use a filter on your pump (in-line)
Screwdriver Assortment
Tap & Die Set

Field Equipment
Field Box
Tool Box
Gas Can-Thinner Cans Are Nice
Oiler Of Some Type
Igniter Battery-You Can Make One With Alkaline Cells-Soldering
Power Panel
Manual Or Electric Fuel Pump
6MM wand size for most heli's
Can of Skoal, OOps for nerves

Just buy what you need!! This is just what I use now-I used to borrow a few I have now.

CyberPilot
You can use a lot of things you have now for heli's too.