Like Jim62 said, an airbrush is a game changer. Cheap ones are fine to start, ebay isn't a bad place to look, though some of the used ones can get really expensive. I have an old Paasche single-action that I bought many years ago that I still use & I love it, but it's only good for broad, even color coats, not so much for superfine details. A quiet airbrush compressor with a tank was a nice upgrade for me... I'd put your $$$ in the compressor first and get a cheaper airbrush to start, then upgrade the actual airbrush later.