Paint comes in a few different varieties. The main three are enamel, acrylic, and lacquer paints. The differences in paint mainly comes down to what the pigments are mixed in. Basically all paints are mixed in oil except acrylic as it is mixed in water.
Generally you should use the same type of paint per project. If you have to or want to use different types, check out my paint layer guide for what is compatible with each other.
Overall it is personal preference if you want to use enamel or acrylic as each has their advantages and disadvantages. If you are not concerned with what kind of paint you want, or what colors are available, then acrylic paint is your best bet. Acrylics are generally the easiest to work with and often sold under the title 'airbrush paint'. Most all the big brands that you can buy on Amazon, Michael's, Hobby Lobby, and chain craft stores are acrylic. These big brands are frequently sold pre-thinned and ready to spray so they are excellent for beginners and general usage. One of the most popular brands is 'Createx' and can be ordered straight from amazon in a variety of colors. Acrylic also has the advantage of being much easier to clean up and quicker dry time but are much easier to scratch and scrape without a clear coat and can dry inside the airbrush causing temporary setbacks.
If you are replicating vintage paint jobs or want something with a different feel and more durable, than enamel is a good choice. Most of the prop makers for Star Wars used enamel airbrush paints as acrylic wasn't widely available yet and/or was not as popular. This is why I always use enamel. I also just prefer to work with it over acrylic.
Boba Fett's paint job was most likely done with UK based company Testor's paint, more specifically the enamel brand called Floquil. However this paint line has been discontinued. The next best thing is UK based company Humbrol and their line of colors. You can order these colors from Humbrol's website for $2.49 a can but shipping is slow and no way to speed it up. Call some local hobby shops and see if any of them sell Humbrol. I found one very close to me that sells them for a little more per can, which I am happy to pay because of convince and supporting businesses that have been hurt by online sales.
Humbrol can be hard to track down in the states so if you want to use enamel and aren't looking for something exact, then Testors's is for you. They are UK based, but unlike Humbrol, are stocked in most all large and small hobby stores. You can check out their color selection on their website.
Other brands exist, and you are more than welcome to explore them, these are just the ones I know of and often see as highly rated.