In the beginning, use simple 2B or 2HB or #2 pencils. I, myself have started using other pencils to SHADE quite recently. But in the beginning, you don't really need them. The best you can get right now is this "Mark Sensing Computer Pencil". It's a typical pencil, just tell a stationary shopkeeper to give you a computer pencil. It's a common #2 pencil used in tests (like SAT etc.). I think that pencil belongs to goldfish. It's black-silver colored pencil with a eraser. Give it a try!
Thanks for asking!