John, first of all welcome to the forum, hope to see you on here regularly, the people here are great. As far as your question, you will have to look in your phone book under "Graphic Arts Supplies" or "Printers Supplies" if you want to buy some. I am a printer by trade ( At last someones asks a question I can answer with some expertise!) and can tell you that metallic printers ink is very expensive at around $30 to $50 per kilo and the minimum you could buy would be a 1 kilo tin. If I were you I would go to a local printers premises with a small airtight container like a plastic film cannister and just ask if you could buy a small amount. I bet you find they will just put some in your container and send you on your way without charging anything or maybe a couple of dollars at the most. That amount would last you a very long time. Sorry I can't help with the rest of your question as I model aircraft and couldn't paint a figure to save my life. Hope this helps.
Cheers....Snowy.