In my opinion, if you want to learn how to use airbrush, you should consider to get a proper one instead of a starter kit. The reason being is that you really need a proper compressor (that can control the air pressure) in order to learn/understand how to use airbrush. The key of successful using an airbrush is to control between the brush size and the pressure. You really need to practice between the two in order to get a hang out of it. Some of the starter kit doesn't allow you to control the air pressure, thus, you can't really do much about it and can't really learn how to use it.
More importantly, airgun and air compressor are really affordable these day thanks to china and taiwin. An air compressor used to cost about $500 to $600 USD 10 years ago, but now, you can get one for about $100 USD. A few of airguns that I am using costs only $30 USD. So, it is really affordable and you can really use it for a very long time given you take care of it nicely. (My old compressor used for 7 years and still working)
In any case, I would recommend you to get a proper airgun/air compressor if you are interested in learning airbrush.
Hope it helps