For a beginner... the essentials are the aircraft, radio, engine, fuel, fuel pump and a couple of spare props. The regulars at the field will rarely mind you needing it borrow a glow ignitor (especially while you are getting lessons) and they will have plenty of tools.

As you gain flying experience, you will see all the stuff that some guys bring... if the plane is properly prepared at home, you should be able to just strap on the wing (connect that aileron lead...), fill the tank, double-check the controls, hook the glow ignitor and fly it.

50% of the time when I go to the field that's less than 2 mi from my house, I don't bring ANY tools. (not even a spare prop)
When I go to the field that's 30 mi, I take anywhere from just enough for minor adjustments, and a couple spare props, to a trailer loaded with enough to build a couple of planes at the field...