A generic 0.5mm mechanical pencil will do. I strongly suggest putting HB lead in it. Make sure it uses a white eraser, not a black or pink one.
If you're just starting out, use the 08 Sakura Pigment Micron to ink. They cost about $2.70 each and can be found at many arts and crafts stores. If there are none there, try the bookstore at a local college.