You can get a cheap airbrush to play with from Harbor Freight:
They sell the inline regulators too. Also water absorbing in line filters.
--also sometimes find used professional quality equipment at Mile High Flea Market. Automotive swap meets are another source. Although the stuff you find used is usually for sale there because it's clogged and dirty.
If you get serious, you can spend a lot of money for professional level equipment and materials. But you get what you pay for.
Kenny, I think your work looks pretty good!