Many people,as Patrick, find the Chinese airbrushes very effective. Ultimately they are going to contain components which are not of the same quality as a better known branded tool but they obviously work well and are adequate as you introduce yourself to airbrushing.
I'd suggest going for a double action
airbrush directly.
The double action is not as complicated as it sounds. The first action is depressing the trigger to allow air to flow. It should always be fully depressed,don't try to control the air flow with this function,that's what a regulater is for.
The second action is pulling the trigger back to introduce the paint. This can be done incrementally.
You will waste a lot less paint with a gravity feed
airbrush and there are less tubes etc to get blocked. Siphon feeds tend to have larger paint reservoirs and there always has to be enough paint in the bottle to allow the siphon tube to suck paint rather than air!
Bunkerbarge has explained the draw backs of canned air very well above. It doesn't take many cans to pay for a modest compressor. A can may give a 28 minute supply of air but I guarantee that a significant proportion of that will be used flushing and cleaning the
airbrush rather than actually painting.
It's a lot to take in but I wish you the best of luck whichever options you go for.
Cheers
Steve