The most essential thing that you want to start a comic book artist is that you should have a lot of themes and ideas in your mind that should attract the readers and also you should be aware about which materials and tools are available and how to use them.
the supplies that are basically needed when you are deciding to begin being a comic book artist are: pencil with a good lead, eraser, supporting board and comic book stand for your reference.
Pencils and ink, of course; then some pre-ruled comic art paper, which you can get from several internet sources. You don't even have to have that, creativity is most important.
You will need a sketch book, a ruler, a pencil, an eraser, some ink pens in many colors, or colored pencils in many colors. You may want to get a scanner so you can upload your artwork onto a computer.
These are not the only supplies you might need, but are good ones to begin with:
11x17 Paper (Goes to 10x15 for borders)
Micron Ink Pens (Various sizes)
Various grades of pencils
Ruler
Toner sheets