If you are planning on painting latex go for acrylic inks like liquitex or FW inks, they are more flexible than regular acrylic paint, it doesn't clog your airbrush, they run faster thru it.
Whoever used to paint with regular acrylics and switch to Inks can tell you about the big difference. You can apply them straight from the bottom or you can dilute them with 99% Isopropyl alcohol or like me that I use windshield washer fluid, which is about under $3 a gallon.
If your pocket can afford it and you don't mind inhaling lethal fumes you can try rubber stamping inks, this is what I'm using at the moment but I wouldn't recommend you to use them until you get a bit more experience handling this type of chemicals, you have to work with naphta which is very dangerous.
So as an advice just stick to acrylic inks and a good varnish or sealer to paint your costume.
Good luck bud.
-Chris