Hi, Thyamis!
Ah, it's good to hear Mr. Roussos is a big star. I certainly enjoyed translating some of his music into Japanese.
Although I have worked professionally as a musician, that work was done when I worked at a translation company here in Japan.
I have heard of Olympos airbrushes, but I don't know much about them.
Nothing's really cheap in Japan, but foreign (non-Japanese) airbrushes are really expensive.
Japanese brushes like Iwata, Gunze, and my favorite, Tamiya, are quite reasonable. I've been using a Tamiya HG Trigger AB for the last 5 years, and I feel no need to use any other.
I don't know of any specific international mail order shops, but I'm sure there's gotta be some out there selling Japanese equipment. Aside from participating in these forums, I don't spend much time using the Internet. That's one reason I have sooo many posts!