You are 100% right, the big kits you find on the internet have stuff you do not want or need.
That being said, if you are looking at the smaller kits, ie the compressor, airbrush, a few stencils and some paint then no that is all needed. Those are the 4 core needs. That is all you need to put on airbrush tattoos.
The "systems" are the ones you need to stay away from, you will be paying for crap you don't need.
If you are just doing this for fun, not wanting to make money then yes all you will need is a compressor, some airbrush tattoo paint (it must be airbrush tattoo paint!) and an airbrush. You will also need a stencil or two, but these can be made. Either out of durable plastic or even thin strong card, you will only be able to use the card stencils once or twice and they wont look perfect!
So if you are doing it for fun: Get a basic kit OR buy a cheap airbrush, cheap compressor, some cheap stencils and a bottle of black paint (or whatever color you want, tribalinkproducts has great prices).
If, however, you want to make money at it, then visit my site below, I have an eguide specifically written so you dont spend more than you need, it even has budget plans.
Hope I helped. You can email me if you have any other questions!