Today I'd like to take a moment to talk about airbrushing basics. I feel that it is an art form that is very under represented here on deviantART and perhaps with a little education on it, more people might become interested in airbrushing.
Airbrushes come with a few different features which I've outlined below to help make an educated guess on what type would best suit you if this is something you're interested in trying.
Suction feed airbrushes suck the paint up into the airbrush. These airbrushes are sometimes easier to hold steady since the bottle can aid in gripping your airbrush well for maximum control (two handed grip). They are also great if you want to lay down the same color to a larger area since you have a larger capacity to hold paint. Another benefit is that it can be much easier to switch colors by simply removing the paint bottle, running your brush clean and attaching the new bottle.
Single action airbrushes are pretty simple, you pull back on the lever and paint comes out in a constant and steady flow until you move the lever back to the off position, or you run out of paint. These airbrushes are generally cheaper than double action ones so may be the way to go if your budget is tight or you do not plan on doing overly detailed work. Single action airbrushes, while certainly worthwhile, do not provide the same versatility that dual action ones will. With single action airbrushes there is no control over the amount of air or paint being drawn through the airbrush while spraying. You can however still adjust these things while not spraying, or simply change your distance from what you are airbrushing to get a better range.
Think of this functionality like you would pressure sensitivity in a drawing tablet. Depending on how far back you pull the lever on these airbrushes, the more or less paint you'll have coming out. This is great especially if you plan on working with small details often. Double action airbrushes tend to be more expensive than single action ones, though the added cost is usually worth the money spent. These airbrushes are more versatile. While these may take a bit more time to master, they really do give you a much broader range of how you can work with your airbrush.
If you are interested in getting into or trying your hand at airbrushing you'll need an air compressor.
Air compressors can range in price from roughly 50$ - 500$ and up. This is usually where the bulk of your start up costs will go when you decide that airbrushing is for you. It is worth noting that while the cheaper air compressors will do what they are meant to do, if you plan on working on larger projects that require you to airbrush for longer periods of time, you will likely want an air compressor with a higher HP/Volume that way you won't need to wait for the compressor to refill in order to continue working.
Air compressors can also be quite loud and noisy so if that is something you do not desire you can either put the compressor in another room and run a long hose to your working area in order to drown out some of the noise. Or, you can also buy a compressor that is specially designed to not be so loud.
There are various types of paint you can use for airbrushing and when all is said and done, the type of paint best suited to your art or project will depend on what exactly you plan on painting, or painting on. I won't go into detail on the various paints since it really does depend on what you plan on airbrushing as to which paints are best but I do want to take a moment to talk about pre mixed vs mixing your own paints.
While mixing your own paints is definitely cheaper, it does come with its own challenges. For example mixing your own paints can give you small clumps you didn't notice which can clog up your needle, or you may make the mixture too runny or too thick and either have paint that is quite runny, or clog up your needle.